Composite bodies and methods of forming the same

ABSTRACT

A composite body is provided that can include abrasive grains and at least one pore within a bond matrix, the abrasive grains including cubic boron nitride (cBN) and the bond matrix including a polycrystalline ceramic phase. The bonded abrasive may have a Modulus of Rupture (MOR) of not less than about 40 MPa. Certain embodiments may have porosity, such as, greater than about 5.0 vol %.

CROSS-REFERENCE TO RELATED APPLICATION(S)

The present application claims priority from U.S. Provisional Patent Application No. 61/922,036, filed Dec. 30, 2013, entitled “COMPOSITE BODIES AND METHODS OF FORMING THE SAME,” naming inventors Susanne Liebelt, Thomas J. Tschernig and Cecile Jousseaume, and said provisional application is incorporated by reference herein in its entirety for all purposes.

FIELD OF THE DISCLOSURE

The present disclosure is directed to composite bodies, and particularly directed to, composite bodies including a bond material and pores within the bond material.

BACKGROUND ART

Abrasives are generally utilized in various machining operations, ranging from fine polishing to bulk material removal and cutting. For example, free abrasives composed of loose particles are used in slurries for polishing applications such as, chemical mechanical polishing (CMP) in the semiconductor industry. Alternatively, abrasives can be in the form of fixed abrasive articles such as, bonded and coated abrasives which can include devices such as, grinding wheels, belts, rolls, disks and the like.

Fixed abrasives generally differ from free abrasives in that fixed abrasives utilize abrasive grains or grit within a matrix of material that fixes the position of the abrasive grains relative to each other. Common fixed abrasive grits can include alumina, silicon carbide, various minerals such as, garnet, as well as superabrasives such as, diamond and cubic boron nitride (cBN). In particular reference to composite bodies, the abrasive grits are fixed in relation to each other in a bond material. While many different bond materials can be used, vitrified bond materials, such as, an amorphous phase glass materials are common. However, performance properties of conventional bonded abrasives having vitrified bonds are limited by the nature of the bond, the composition of the abrasive grains and the presence and composition of material surrounding pore within the bond. Notably, the properties of pores within the bond (i.e., pore size, porosity, pore size distribution, microstructure of material surrounding pores) affect the microstructure of the abrasive tool as a whole, playing a role in the effectiveness of the grinding or polishing process.

The industry continues to need bonded abrasives having improved properties.

SUMMARY

According to a first aspect, a composite body is provided which can include a bond material may include a ceramic material and a pore within the ceramic material. The bond material that may include a region at a surface of the pore. The region may include a first pore defining composition distinct from a composition of the ceramic material. The first pore defining composition may have a melting point not less than a melting point of the composition of the ceramic material.

According to a second aspect, a composite body is provided which can include a bond material that may include a ceramic material and a pore within the ceramic material. The bond material may include a peripheral region at a surface defining the pore. The peripheral region may extend for a depth into the bond material. The peripheral region may include a first pore defining composition distinct from a composition of the ceramic material. The first pore defining composition may have a melting point not less than a melting point of the composition of the ceramic material.

According to yet another aspect, a composite body is provided which can include a bond material that may include a ceramic material and a pore within the ceramic material. The bond material may include a region at a surface of the pore. The region at a surface of the pore may include a first pore defining composition distinct from a composition of the ceramic material. The first pore defining composition may have a first melting point (Tm1) and the composition of the ceramic material has a second melting point (Tm2). The differential melting point between the first melting point and the second melting point may be defined as [Tm1-Tm2]. The differential melting point may be at least about 0.5° C. and not greater than about 1000° C.

According to still another aspect, a composite body is provided which can include a bond material that may include a ceramic material and a pore with-in the ceramic material. The bond material may include a region of the bond material at a surface of the pore. The region at the surface of the pore may include a first pore defining composition distinct from a composition of the ceramic material. The first pore defining composition may have a first hardness (H1) and the composition of the ceramic material may have a second hardness (H2). The first hardness may be not less than the second hardness.

According to yet another aspect, a method of forming a composite body may include providing a composite body mixture that may include a bond material precursor powder and a pore former comprising a first pore former composition. The method further can include forming the composite body mixture into a composite body comprising a bond material including a ceramic material and a region surrounding a pore in the bond material. The ceramic material may include a composition and the region surrounding the pore may include a first pore defining composition. The first pore defining composition may have a melting point not less than a melting point of a composition of the ceramic material.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure may be better understood, and its numerous features and advantages made apparent to those skilled in the art by referencing the accompanying drawings.

FIG. 1 includes a flow chart illustrating a process for forming a composite body according to one embodiment.

FIG. 2 includes a cross-sectional illustration of a pore former in accordance with an embodiment.

FIG. 3 includes a cross-sectional illustration of a portion of a composite body in accordance with an embodiment.

FIGS. 4A and 4B are images of sections of conventional composite bodies illustrating merger of the pore former with the bond material.

FIG. 5 is an image of a section of a composite body according to an embodiment illustrating clear demarcation of the pore former within the bond material.

The use of the same reference symbols in different drawings indicates similar or identical items.

DETAILED DESCRIPTION

The following is generally directed to composite bodies. In particular, the composite bodies may include more than one component, including for example, a bond material and a pore contained within the bond material. In particular instances, the composite bodies may be utilized in various applications, including for example abrasives (e.g., fixed abrasives), medical industries, building and construction industries, aerospace industries, and a combination thereof. In one particular embodiment, the composite body may be a bonded abrasive body including abrasive particles contained within a bond material, and pores contained within the bond material.

FIG. 1 includes a flow chart illustrating a method of forming a composite body in accordance with an embodiment. As illustrated in FIG. 1, a process 100 can be initiated at step 101 by providing a composite body mixture that may include a bond material precursor powder and a pore former, which may include at least a first pore former composition. In accordance with an embodiment, the composite body mixture may be a dry mixture. However, in still other embodiments, the composite body mixture may be a wet mixture, such as, in the form of a slurry, which may facilitate formation of a particular shape of the body. Moreover, as will be appreciated and described herein, the composite body mixture may include other components, including, for example, abrasive particles, additives or a combination thereof.

In accordance with an embodiment, the bond material precursor powder may include one or more powder components configured to be treated and formed into a bond material of the composite body. Notably, forming of the composite body from a composite body mixture, as will be described herein, may include changing the bond material precursor powder to a bond material, which may include a ceramic material.

The bond material precursor powder may generally include a glass (amorphous) powder, such that not less than about 80 wt % of the glass is amorphous phase. According to a particular embodiment, the glass powder can include a greater content of amorphous phase, such as, not less than about 90 wt % or even not less than about 95 wt % amorphous phase.

Generally, formation of a glass powder can be completed by mixing a suitable proportion of raw materials and melting the mixture of raw materials to form a glass at high temperatures. After sufficient melting and mixing of the glass, the glass can be cooled (quenched) and crushed to a powder. The glass powder may be further processed, such as, by a milling process, to provide a glass powder having a suitable particle size distribution. The glass powder may have an average particle size of not greater than about 100 microns. In a particular embodiment, the glass powder has an average particle size of not greater than 75 microns, such as, not greater than about 50 microns or even not greater than about 10 microns. However, the average particle size of the glass powder can be within a range of between about 5.0 microns and about 75 microns.

The composition of the glass powder may be described using the equation aM₂O-bMO-cM₂O₃-dMO₂. As illustrated by the equation, the glass powder can include more than one metal oxide, such that the oxides are present together as a compound oxide material. In one particular embodiment, the glass powder can include metal oxide compounds having monovalent cations (1+), such as, those metal oxide compounds represented by the generic formula M₂O. Suitable metal oxide compositions represented by M₂O can include compounds, such as, Li₂O, Na₂O, K₂O, and Cs₂O.

According to another embodiment, and as provided in the general equation, the glass powder may include other metal oxide compounds. In particular, the glass powder may include metal oxide compounds having divalent cations (2+), such as, those metal oxide compounds represented by the generic formula MO. Suitable metal oxide compounds represented by MO can include compounds such as, MgO, CaO, SrO, BaO, and ZnO.

Additionally, the glass powder may include metal oxide compounds having trivalent cations (3+), particularly those metal oxide compounds represented by the generic formula M₂O₃. Suitable metal oxide compounds represented by M₂O₃ can include compounds such as, Al₂O₃, B₂O₃, Y₂O₃, Fe₂O₃, Bi₂O₃, and La₂O₃.

Notably, as indicated in the general equation above, the glass powder can include metal oxide compounds having cations of a 4+ valence state, as represented by MO₂. As such, suitable MO₂ compounds may include SiO₂, TiO₂, and ZrO₂.

In further reference to the composition of the glass powder represented by the generic equation aM₂O-bMO-cM₂O₃-dMO₂, the coefficients (a, b, c, and d) may be provided to indicate the amount (mol fraction) of each of the different types of metal oxide compounds (M₂O, MO, M₂O₃, and MO₂) that can be present within the glass powder. As such, coefficient “a” generally represents the total amount of the M₂O metal oxide compounds within the glass powder. The total amount of M₂O metal oxide compounds within the glass powder may be generally within a range between about 0.30 and about 0.0. According to a particular embodiment, the total amount of M₂O metal oxide compounds may be present within a range of about 0.15 and about 0.0, and more particularly, within a range of about 0.10 and about 0.0.

In reference to the presence of MO metal oxide compounds containing a divalent cation, the total amount (mol fraction) of such compounds can be defined by the coefficient “b”. Generally, the total amount of MO metal oxide compounds within the glass powder may be within a range between about 0.60 and about 0.0. According to a particular embodiment, the amount of MO metal oxide compounds may be within a range of between about 0.45 and about 0.0, and more particularly, within a range of between about 0.35 and about 0.15.

Additionally, the amount of M₂O₃ metal oxide compounds containing a trivalent cation species within the glass powder may be represented by the coefficient “c”. As such, the total amount (mol fraction) of M₂O₃ oxide compounds may be generally within a range of between about 0.60 and about 0.0. According to one particular embodiment, the amount of M₂O₃ metal oxide compounds within the glass powder may be within a range of between about 0.40 and about 0.0, and more particularly, within a range of between about 0.30 and about 0.10.

The presence of MO₂ metal oxide compounds containing a 4+ cation species as described in the general equation aM₂O-bMO-cM₂O₃-dMO₂ may be represented by the coefficient “d”. Generally, the total amount (mol fraction) of MO₂ oxide compounds within the glass powder may be within a range of between about 0.80 and about 0.20. In one particular embodiment, the amount of MO₂ metal oxide compounds within the glass powder may be within a range of between about 0.75 and about 0.30, and more particularly, within a range of between about 0.60 and about 0.40.

In particular reference to MO₂ metal oxide compounds, particular embodiments may utilize a glass powder that can include silicon dioxide (SiO₂) such that the glass powder may be a silicate-based composition. In particular reference to only the presence of silicon dioxide within the glass powder, the glass powder may include not greater than about 80 mol % silicon dioxide. According to another embodiment, the glass powder may include not greater than about 70 mol % or even not greater than about 60 mol % silicon dioxide. Still, in particular embodiments, the amount of silicon dioxide in the glass powder may be not less than about 20 mol %. As such, the amount of silicon dioxide in the glass powder may be generally within a range of between about 30 mol % and about 70 mol %, and particularly within a range between about 40 mol % and about 60 mol %.

In further reference to M₂O₃ metal oxide compounds, certain compositions of the glass powder include aluminum oxide (Al₂O₃) particularly in addition to silicon dioxide, such that the glass powder may be an aluminum silicate. As such, in particular reference to only the presence of aluminum oxide, generally the glass powder can include not greater than about 60 mol % Al₂O₃. In other embodiments, the glass powder can include aluminum oxide in lesser amounts, such as, not greater than about 50 mol % or even not greater than about 40 mol %. The glass powder may incorporate aluminum oxide within a range between about 5.0 mol % to about 40 mol %, and particularly within a range between about 10 mol % and about 30 mol %.

According to a particular embodiment, the glass powder can include at least one of magnesium oxide and lithium oxide in addition to silicon dioxide, and more particularly, in addition to silicon dioxide and aluminum oxide. As such, the amount of magnesium oxide within the glass powder may be generally not greater than about 45 mol %, such as, not greater than 40 mol % or even, not greater than 35 mol %. The glass powder compositions having magnesium oxide, may utilize an amount within a range between about 5 mol % and about 40 mol %, and particularly within a range between about 15 mol % and about 35 mol %. Magnesium-containing aluminum silicate glasses may be referred to as MAS glasses having a magnesium aluminum silicate composition.

According to another embodiment, the glass powder can include lithium oxide. As such, the amount of lithium oxide within the glass powder may be generally not greater than about 45 mol %, such as, not greater than 30 mol % or even, not greater than 20 mol %. The glass powder compositions having lithium oxide, may utilize an amount within a range between about 1.0 mol % and about 20 mol %, and particularly within a range between about 5.0 mol % and about 15 mol %. Lithium-containing aluminum silicate glasses may be referred to as LAS glasses having a lithium aluminum silicate composition.

In other embodiments, the glass powder can include barium oxide. As such, the amount of barium oxide within the glass powder may be generally not greater than about 45 mol %, such as, not greater than 30 mol % or even, not greater than 20 mol %. The glass powder compositions having barium oxide, may utilize an amount within a range between about 0.1 mol % and about 20 mol %, and more particularly, within a range between about 1.0 mol % and about 10 mol %. Barium-containing aluminum silicate glasses may be referred to as BAS glasses having a barium aluminum silicate composition.

In other embodiments, the glass powder can include calcium oxide. As such, the amount of calcium oxide within the glass powder may be generally not greater than about 45 mol %, such as, not greater than 30 mol % or even, not greater than 20 mol %. The glass powder compositions having calcium oxide may utilize an amount within a range between about 0.5 mol % and about 20 mol %, and particularly within a range between about 1.0 mol % and about 10 mol %. In some embodiments, calcium oxide may be present in systems utilizing other metal oxide compounds mentioned above, notably in combination with the MAS or BAS glasses. The calcium oxide can form a compound oxide, for example a calcium magnesium aluminum silicate (CMAS) or calcium barium magnesium aluminum silicate (CBAS).

As described above, the glass powder can include other metal oxide compounds. According to a particular embodiment, the glass powder may include boron oxide. Generally, the amount of boron oxide within the glass powder may be not greater than about 45 mol %, such as, not greater than 30 mol % or even, not greater than 20 mol %. The glass powder having boron oxide may utilize an amount within a range between about 0.5 mol % and about 20 mol %, and particularly within a range between about 2.0 mol % and about 10 mol %.

In another particular embodiment, the glass powder can include other metal oxides, as described above, such as, for example, Na₂O, K₂O, Cs₂O, Y₂O₃, Fe₂O₃, Bi₂O₃, La₂O₃, SrO, ZnO, TiO₂, P₂O₅, and ZrO₂. Such metal oxides can be added as modifiers to control the properties and processability of the glass powder and the resulting bond material. Such modifiers may be present in the glass powder in an amount of not greater than about 20 mol %. According to another embodiment, such modifiers may be present in the glass powder in an amount of not greater than about 15 mol %, such as, not greater than about 10 mol %. Glass powder compositions with modifiers may utilize an amount within a range between about 1.0 mol % and about 20 mol %, and more particularly, within a range between about 2.0 mol % and about 15 mol %.

As further indicated, the composite body mixture may include a pore former. In accordance with an embodiment, the pore former may be a component configured to create porosity in the finally-formed composite body. Notably, the pore former may have a particular size and shape, which may facilitate formation of a particular size and shape of porosity within the finally-formed composite body. In certain instances, the pore former may be obtained from readily-available, commercial sources. And still other embodiments, the pore former can be formed independent of the composite body. For example, in certain instances, the process of forming a pore former can include obtaining a precursor pore forming agent of a suitable size and shape. The precursor pore former agent may be hollow spheres of organic material, including for example polymer bubbles.

In accordance with an embodiment, the process of forming a pore former can further include coating the precursor pore forming agent with a particular composition. In certain instances, the precursor pore forming agent may be coated with a slurry comprising at least a first pore forming composition precursor material, which may be configured, upon further treatment, to combine with and/or convert the precursor pore forming agent to form the first pore former composition. After coating the precursor pore forming agent with the first pore forming composition precursor material in a suitable manner, the process can continue by treating the coated precursor pore forming agent to form the pore former, which can include the first pore former composition.

Certain exemplary processes for treating the coated precursor forming agent may include heating of the coated precursor pore forming agent to a suitable temperature to volatilize a polymer component of the precursor pore forming agent and solidify or densify the first pore forming composition precursor material. As such, in particular instances the process of heating can facilitate volatilization of the polymer material and solidification of the first pore former composition precursor material to form hollow spheres, wherein the walls may be made of the first pore former composition. In further instances, the process of treating can include a heating process and a controlled cooling process to facilitate the formation of pore formers, wherein the wall of the pore formers may be made of a first pore former composition, which may include a polycrystalline material.

In particular instances, the first pore former composition may include a ceramic material. As used herein, a ceramic material may refer to inorganic compositions, including, for example, a combination of a metal element and non-metal element. Furthermore, a ceramic material may include materials having an amorphous phase, crystalline phase, polycrystalline phase, and a combination thereof. In at least one embodiment, the first pore former composition of the pore former may include a content of amorphous phase material, such as, a glassy material. In still other embodiments, the first pore former composition of the pore former may include a polycrystalline material. Still, it will be appreciated that in certain instances, the first pore former composition of the pore former can include a combination of amorphous phase material and polycrystalline phase material. In still another embodiment, the first pore former composition of the pore former can include a polycrystalline material including a crystalline material selected from the group consisting of cordierite, indialite, enstatite, sapphirine, anorthite, celsian, diopside, spinel, beta-spodumene, and a combination thereof.

FIG. 2 includes a cross-sectional view of a pore former in accordance with an embodiment. As illustrated, the pore former 200 can include a body 201. The body can be in the form of a hollow object having a void 202 contained within the interior of the body 201. In more particular instances, the pore former 200 can be in the shape of a hollow spheroid, generally having a spherical-like three-dimensional shape. In accordance with at least one embodiment, the pore former 200 can be in the form of a hollow spheroid, wherein the body 201 includes a wall 205, which defines the interior space 202. As noted above, the wall 205 of the body 201 may include the first pore former composition.

Furthermore, the wall 205 may have a particular thickness 203, such as, a thickness of not greater than about 200 μm. In other embodiments, the thickness 203 of the wall can be not greater than about 180 μm, not greater than about 150 μm, not greater than about 130 μm, not greater than about 100 μm or even not greater than about 80 μm. Still, in at least one non-limiting embodiment, the thickness 203 of the wall can be at least about 1 μm, such as, at least 5 μm or even at least about 10 μm. It will be appreciated that the thickness 203 of the wall 205 can be any value within a range between any of the minimum and maximum values noted above.

The amount of the pore former provided in the mixture may be not greater than about 35 vol %. In another embodiment, the mixture can include not greater than about 30 vol % of the pore former, such as, not greater than about 20 vol % or even not greater than about 15 vol % of the pore former. According to a particular embodiment, the mixture can include an amount of pore former in a range of between about 1.0 vol %, and about 35 vol %, and more particularly, within a range between about 5.0 vol % and about 25 vol %.

As further indicated, the composite body mixture may further include abrasive particles. Generally, the composite body mixture may include not less than about 25 vol % abrasive particles. According to a particular embodiment, the mixture can include not less than about 40 vol % abrasive particles, such as, not less than about 45 vol % or even not less than about 50 vol % abrasive particles. In still other non-limiting embodiments, the amount of abrasive particles may be limited such that the composite body mixture can include not greater than about 60 vol % abrasive particles. In particular, the abrasive particles within the mixture may be generally present in an amount within a range between about 30 vol % and about 55 vol %.

In reference to the abrasive particles, generally the abrasive particles include hard, abrasive materials, and particularly include superabrasive materials. According to a particular embodiment, the abrasive particles may be superabrasive particles, such that they may be either diamond or cubic boron nitride (cBN). In a particular embodiment, the abrasive particles include cubic boron nitride, and more particularly, the abrasive particles consist essentially of cubic boron nitride.

The abrasive particles may generally have an average grain size of not greater than about 500 microns, such as, not greater than about 400 microns, not greater than about 300 microns, not greater than about 250 microns, not greater than about 200 microns, not greater than about 180 microns, not greater than about 160 microns, not greater than about 140 microns, not greater than about 120 microns, not greater than about 100 microns, not greater than about 80 microns, not greater than about 60 microns, not greater than about 40 microns or even not greater than about 20 microns. According to other non-limiting embodiments, the abrasive particles may have an average grain size of at least about 1.0 micron, such as, at least about 5 microns, at least about 10 microns, at least about 15 microns, at least about 20 microns, at least about 25 microns, at least about 30 microns, at least about 35 microns, at least about 40 microns, at least about 60 microns, at least about 80 microns or even at least about 100 microns. It will be appreciated that the abrasive particles may have an average grain size of any value within a range between any of the minimum and maximum values noted above.

According to another embodiment, the abrasive particles may have a major component of cubic boron nitride. In certain embodiments, a certain percentage of the abrasive particles which generally may be otherwise cubic boron nitride can be replaced with substitute abrasive particles, such as, aluminum oxide, silicon carbide, boron carbide, tungsten carbide, and zirconium silicate. As such, the amount of substitute abrasive particles may be generally not greater than about 40 vol % of the total abrasive particles, such as, not greater than about 25 vol % or even not greater than about 10 vol % for the total volume of the abrasive particles.

In reference to the amount of bond material precursor powder combined with the pore former and abrasive grains in the composite body mixture, the composite body mixture may include not less than about 10 vol % bond material precursor powder, such as, not less than about 15 vol % bond material precursor powder. Still, the amount of bond material precursor powder may be limited, such that the mixture can include not greater than about 60 vol % bond material precursor powder, such as, not greater than about 50 vol % bond material precursor powder or even not greater than about 40 vol % bond material precursor powder. In particular, the mixture generally can include an amount of bond material precursor powder within a range between about 10 vol % and about 30 vol %.

As further indicated, the composite body mixture can include other additives, such as, a binder. Generally, the binder may be an organic material. Suitable binder materials can include organic materials containing glycol (e.g., polyethylene glycol), dextrin, resin, glue or alcohol (e.g., polyvinyl alcohol) or combinations thereof. Generally, the mixture can include not greater than about 15 vol % of a binder, such as, not greater than about 10 vol %. According to one particular embodiment, the binder may be provided in the mixture within a range between about 2.0 vol % and about 10 vol %.

Referring back to FIG. 1, after providing the composite body mixture in step 101, the process may continue at step 102 by forming the composite body mixture into a composite body including a bond material. The bond material may include a ceramic material and at least one pore within the bond material wherein a region of the bond material at a surface of the pore may include a first pore defining composition distinct from the ceramic material. Notably, the first pore defining composition may be substantially the same as the first pore former composition.

In accordance with an embodiment, the process of forming may include any suitable process, such as, molding, pressing, depositing, casting, extruding, heating, cooling, crystallization, melting, and a combination thereof. For example, after providing the composite body mixture at step 101, step 102 may include forming the composite body mixture into a green article. Forming of the mixture into a green article may include forming processes that give the green article the desired final contour or substantially the desired final contour. As used herein, the term “green article” refers to a piece that may be not fully processed (e.g., heat treatment). According to a one embodiment, the forming process may be a molding process.

After forming the green article, step 102 may further include a pre-firing step. Generally the pre-firing step can include heating the green article to facilitating evolving volatiles (e.g., water and/or organic materials or pore formers). As such, heating of the mixture generally can include heating to a temperature of greater than about room temperature (22° C.). According to one embodiment, the pre-firing process can include heating the green article to a temperature of not less than about 100° C., such as, not less than about 200° C. or even not less than about 300° C. According to a particular embodiment, heating may be completed at a temperature of at least about 22° C., such as at least about 50° C., at least about 100° C., at least about 150° C., at least about 200° C., at least about 250° C., at least about 300° C., at least about 400° C., at least about 500° C., at least about 600° C., at least about 700° C., at least about 800° C. or even at least about 900° C. According to still other embodiments, heating may be completed at a temperature of not greater than about 1000° C., such as, not greater than about 950° C., not greater than about 900° C., not greater than about 850° C., not greater than about 800° C., not greater than about 700° C., not greater than about 600° C., not greater than about 500° C., not greater than about 400° C., not greater than about 300° C., not greater than about 200° C. It will be appreciated that heating may occur at a temperature within a range between any of the minimum and maximum values noted above.

After pre-firing the green article, step 102 may further include heating the composite body mixture to a temperature sufficient to change the bond material precursor powder to a three-dimensional matrix of bond material. Such a process may include treating of the mixture at a temperature sufficient to melt a significant portion of the bond material precursor powder. Notably, in one aspect, the process of treating, more particularly, heating of the mixture at a temperature, may be at a temperature sufficient to maintain a substantially solid state of the first pore former composition. Such a heating process may further limit the dissociation of the first pore former composition into the bond material. In accordance with an embodiment, the process may include treating the mixture at a temperature, wherein the bond material precursor powder has a viscosity less than a viscosity of the first pore former composition. In such instances, the bond material precursor powder may be converted to a more liquid state to facilitate flowing of the material over other components of the mixture and facilitate formation of a composite body in accordance with an embodiment.

In accordance with a particular aspect, heating the composite body mixture may include heating the mixture to a temperature below a melting point of the first pore former composition. More particularly, the process of heating may include heating the mixture to a temperature that may be above a melting point of the bond material precursor powder.

In certain embodiments, heating the composite body mixture may include heating the green article to a temperature of at least about 600° C., such as, at least about 630° C., at least about 650° C., at least about 680° C., at least about 700° C., at least about 730° C., at least about 750° C., at least about 780° C., at least about 800° C., at least about 830° C., at least about 850° C., at least about 880° C., at least about 900° C., at least about 930° C., at least about 950° C., at least about 980° C., at least about 1000° C., at least about 1030° C., at least about 1050° C., at least about 1080° C., at least about 1100° C., at least about 1130° C., at least about 1150° C., at least about 1180° C., at least about 1200° C., at least about 1230° C., at least about 1250° C., at least about 1280° C., at least about 1300° C., at least about 1330° C., at least about 1350° C., at least about 1380° C., at least about 1400° C., at least about 1430° C., at least about 1450° C., at least about 1480° C., at least about 1500° C., at least about 1530° C., at least about 1550° C. or even at least about 1580° C. According to still other embodiments, heating the composite body mixture may include heating the green article to a temperature of not greater than about 1600° C., such as, not greater than about 1580° C., not greater than about 1550° C., not greater than about 1530° C., not greater than about 1500° C., not greater than about 1480° C., not greater than about 1450° C., not greater than about 1430° C., not greater than about 1400° C., not greater than about 1380° C., not greater than about 1350° C., not greater than about 1330° C., not greater than about 1300° C., not greater than about 1280° C., not greater than about 1250° C., not greater than about 1230° C., not greater than about 1200° C., not greater than about 1180° C., not greater than about 1150° C., not greater than about 1150° C., not greater than about 1130° C., not greater than about 1100° C., not greater than about 1080° C., not greater than about 1050° C., not greater than about 1030° C., not greater than about 1000° C., not greater than about 980° C., not greater than about 950° C., not greater than about 930° C., not greater than about 900° C., not greater than about 880° C., not greater than about 850° C., not greater than about 830° C., not greater than about 800° C., not greater than about 780° C., not greater than about 750° C., not greater than about 730° C., not greater than about 700° C., not greater than about 680° C., not greater than about 650° C. or even not greater than about 630° C. It will be appreciated that heating the composite body mixture may include heating the green article to any temperature within a range between any of the minimum and maximum values noted above.

In addition to heating at high temperatures, heating may be generally carried out in a controlled atmosphere. According to one embodiment, a controlled atmosphere can include a non-oxidizing atmosphere. Examples of a non-oxidizing atmosphere can include an inert atmosphere, such as, one using a noble gas. According to one particular embodiment, the atmosphere consists of nitrogen, such as, not less than about 90 vol % nitrogen. Other embodiments utilize a greater concentration of nitrogen, such as, not less than about 95 vol % or even not less than 99.99 vol % of the atmosphere may be nitrogen. According to one embodiment, the process of heating in a nitrogen atmosphere may begin with an initial evacuation of the ambient atmosphere to a reduced pressure of not greater than about 0.05 bar. In a particular embodiment, this process may be repeated such that the heating chamber may be evacuated numerous times. After the evacuation, the heating chamber can be purged with oxygen-free nitrogen gas.

In further reference to the heating process, generally heating may be carried out for a particular duration. As such, heating may be generally carried out for a duration of not less than about 10 minutes, such as, not less than about 60 minutes or even not less than about 240 minutes at the heating temperature. Generally, heating may be carried out for a duration between about 20 minutes to about 4 hours, and particularly between about 30 minutes and about 2 hours.

In accordance with an embodiment, after heating the composite body mixture, step 102 may further include a controlled cooling and crystallization process. The controlled cooling and crystallization process may be conducted after a heating process. More particularly, the controlled cooling and crystallization process may be conducted after melting at least a portion of the bond material precursor powder to form a three-dimensional matrix of bond material comprising a ceramic material. In one aspect, the use of a controlled cooling and crystallization process may facilitate formation of at least one polycrystalline phase within the bond material. Furthermore, a controlled cooling process may be utilized to facilitate formation of at least one crystalline or polycrystalline phase within the first pore defining composition.

Generally, after heating, the ramp rate from the heating temperature can be controlled to facilitate crystallization of the bond material. The cooling rate from the heating temperature may be not greater than about 30° C./hr, such as, not greater than about 25° C./hr or even not greater than about 20° C./min. According to a particular embodiment, cooling may be undertaken at a rate of not greater than about 15° C./hr.

Additionally, the controlled cooling and crystallization process can include a hold process wherein the composite body may be held at a crystallization temperature above the glass transition temperature (T_(g)) of the bond material. The composite body can be cooled to a temperature of not less than about 100° C. above T_(g), such as, not less than about 200° C. above T_(g) or even not less than about 300° C. above T_(g). Generally, the crystallization temperature may be not less than about 800° C., such as, not less than about 900° C. or even not less than about 1000° C. Particularly, the crystallization temperature may be within a range between about 900° C. to about 1300° C., and more particularly, within a range between about 950° C. to about 1200° C.

During the controlled cooling and crystallization process, the composite body may be generally held at the crystallization temperature for a duration of not less than about 10 min. In one embodiment, the composite body may be held at the crystallization temperature for not less than about 20 min, such as, not less than about 60 min or even not less than about 2 hours. Typical durations for holding the bonded abrasive at the crystallization temperature may be within a range between about 30 min to about 4 hours, and particularly within a range of about 1 hour to about 2 hours. It will be appreciated, that the atmosphere during this optional cooling and crystallization process may be the same as the atmosphere during the heating process and accordingly can include a controlled atmosphere, particularly an oxygen-free, nitrogen-rich atmosphere.

According to certain embodiments, the composite body generally can include a degree of porosity that may be not less than about 5.0 vol % of the total volume of the composite body. The amount of porosity may be more, such that the porosity may be not less than about 10 vol %, such as, not less than about 15 vol %, about 20 vol % or even, not less than about 30 vol % of the total volume of the bonded abrasive. Still, the amount of porosity may be limited, such that the porosity may be not greater than about 70 vol %, such as, not greater than about 60 vol % or even not greater than about 50 vol %. According to a particular embodiment, the porosity of the composite body may be within a range of between about 20 vol % and about 50 vol %. Such porosity may be generally a combination of both open and closed porosity.

It will be further appreciated, that in certain embodiments, the composite body mixture may include “natural porosity” or the existence of bubbles or pores within the mass of the mixture of abrasive grains, bonded material precursor powder, and other additives. Accordingly, this natural porosity can be maintained in the final composite body depending upon the forming techniques. As such, in particular embodiments, the natural porosity within the mixture, in addition to the pore former, may be utilized and maintained throughout the forming and heating process to form a final composite body having the desired amount of porosity. Generally, the natural porosity of the mixture may be not greater than about 40 vol %. Although, in particular embodiments the natural porosity within the mixture may be less, such as, not greater than about 25 vol % or not greater than about 15 vol %. Generally, the amount of natural porosity within the mixture may be within a range between about 5.0 vol % and about 25 vol %.

In further reference to the porosity of the composite body, the average pore size may be generally not greater than about 500 microns, such as, not greater than about 500 microns, such as, not greater than about 400 microns, not greater than about 300 microns, not greater than about 250 microns, not greater than about 200 microns, not greater than about 180 microns, not greater than about 160 microns, not greater than about 140 microns, not greater than about 120 microns, not greater than about 100 microns, not greater than about 80 microns, not greater than about 60 microns, not greater than about 40 microns or even not greater than about 20 microns. According to other non-limiting embodiments, the composite body may have an average pore size of at least about 1.0 micron, such as, at least about 5 microns, at least about 10 microns, at least about 15 microns, at least about 20 microns, at least about 25 microns, at least about 30 microns, at least about 35 microns, at least about 40 microns, at least about 60 microns, at least about 80 microns or even at least about 100 microns. It will be appreciated that the composite body may have an average pore size of any value within a range between any of the minimum and maximum values noted above.

FIG. 3 includes a cross-sectional view of a portion of a composite body in accordance with an embodiment, as illustrated, the composite body 300 can include a body 301 including bond material 302 in a three-dimensional matrix and abrasive particles 303 contained within the three-dimensional matrix of bond material 302. As further illustrated, the composite body 300 can include at least one pore 304. In particular embodiments, a plurality of pores 304 may be dispersed throughout the bond material 302. In accordance with an embodiment, the pore 304 can include an interior surface 305 defining the pore within the bond material 302. As further illustrated, the surface, in particular interior surface 305 of the pore 304 can define a first pore defining composition, which may be essentially the same as the first pore forming composition. The first pore defining composition may be distinct from the composition of the ceramic material defining the bond material 302.

In accordance with one aspect, the region of the bond material 302 at a surface 305 of the pore 304 can define a first pore defining composition having a melting point not less than a melting point of the composition of the ceramic material defining the bond material 302. In more particular instances, the first pore defining composition can have a first melting point (Tm1) and the composition of the ceramic material defining the bond material 302 can have a second melting point (Tm2). The differential melting point between the first melting point and the second melting point, defined by the equation |(Tm1-Tm2)|, can be within a range between at least about 0.5° C. and not greater than about 200° C. Still, in more particular instances, the differential melting point between the first melting point and the second melting point can be at least about 1° C., such as, at least about 2° C., at least about 3° C., at least about 4° C., at least about 5° C., at least about 6° C., at least about 7° C., at least about 8° C., at least about 9° C., at least about 10° C., at least about 12° C., at least about 15° C., at least about 18° C., at least about 20° C., at least about 25° C., at least about 30° C., at least about 35° C., at least about 40° C., at least about 45° C., at least about 50° C., at least about 55° C., at least about 100° C., at least about 200° C., at least about 300° C., at least about 400° C., at least about 500° C., at least about 600° C., at least about 700° C., at least about 800° C. or even at least about 900° C. In yet another non-limiting embodiment, the differential melting point can be not greater than about 1000° C., such as, not greater than about 900° C., not greater than about 800° C., not greater than about 700° C., not greater than about 600° C., not greater than about 500° C., not greater than about 400° C., not greater than about 300° C., not greater than about 200, not greater than about 190° C., not greater than about 180° C., not greater than about 170° C., not great than about 160° C., not greater than about 150° C., not greater than about 140° C., not greater than about 130° C., not greater than about 120° C., not greater than about 110° C., not greater than about 100° C., not greater than about 90° C., not greater than about 80° C., not greater than about 70° C., not greater than about 60° C. or even not greater than about 50° C. It will be appreciated that the differential melting point can be any value within a range between any of the minimum and maximum temperatures noted above.

In accordance with an embodiment, the first pore defining composition can have a melting point (Tm1) of at least about 1100° C. In still other embodiments, the first pore defining composition can have a melting point that may be greater, such as, at least about 1200° C., at least about 1300° C. or even at least about 1350° C. Still, in another non-limiting embodiment, the first pore defining composition can have a melting point of not greater than about 1800° C., such as, not greater than about 1700° C. or even not greater than about 1600° C. It will be appreciated that the first pore defining composition can have a melting point of any value within a range between any of the minimum and maximum values noted above.

In accordance with an embodiment, the composition of the ceramic material can have a particular melting point. For example, the composition of the ceramic material can have a melting point of at least about 1000° C., such as, at least about 1100° C., at least about 1200° C. or even at least about 1300° C. Still, in at least one non-limiting embodiment, the composition of the ceramic material can have a melting point of not greater than about 1700° C., such as, not greater than about 1600° C. or even not greater than about 1500° C. It will be appreciated that the composition of the ceramic material can have a melting point within a range between any of the above minimum and maximum values.

In one aspect, the first pore defining composition can have a first melting point (Tm1) and the composition of the ceramic material can have a second melting point (Tm2), and a percent difference between the first melting point and the second melting point may be defined as a differential melting point percentage defined by the equation [Tm1−Tm2)|/(0.5*(Tm1+Tm2))]*100%. In particular instances, the differential melting point percentage can be at least about 1%, such as, at least about 2%, at least about 3%, at least about 5%, at least about 8%, at least about 10%, at least about 12%, at least about 15%, at least about 18%, at least about 20%, at least about 22%, at least about 25%, at least about 28% or even at least about 30%. Still, in one non-limiting embodiment, the differential melting point percentage can be not greater than about 99%, such as, not greater than about 90%, not greater than about 80%, not greater than about 70%, not greater than about 60%, not greater than about 50%, not greater than about 45%, not greater than about 40%, not greater than about 35%, not greater than about 30%, not greater than about 25%, not greater than about 20%, not greater than about 18%, not greater than about 15%, not greater than about 12%, not greater than about 10% or even not greater than about 8%. It will be appreciated that the differential melting point percentage can be any value within a range between any of the minimum and maximum percentages noted above.

As further illustrated in FIG. 3, the bond material 302 can include a peripheral region 306 extending around at least a portion of the surface 305 defining the pore 304. Furthermore, the peripheral region 306 can define a depth between the surface 305 and a distance into the bond material defined by the first pore defining composition. Notably, the first pore defining composition can be distinct from the composition of the ceramic material making up the bond material 302. In accordance with an embodiment, the depth 307 of the peripheral region 306 may be not greater than a diameter 308 of the pore as defined by the greatest distance between the interior surface 305 as viewed in two-dimension (e.g. through SEM or other optical micrograph). In still other embodiments, the depth 307 of the peripheral region 306 can be greater than a diameter 308 of the pore. In still another alternative embodiment, the depth 307 of the peripheral region 306 may be substantially related to a wall thickness of the pore former. In particular instances, the depth 307 of the peripheral region 306 may be not greater than about 200 μm, such as, not greater than about 180 μm, not greater than about 150 μm, not greater than about 100 μm or even not greater than about 80 μm. Still, in other non-limiting embodiments, the depth 307 of the peripheral region 306 can be at least about 1 μm, such as, at least about 3 μm, at least about 5 μm or even at least about 10 μm. It will be appreciated that the depth 307 of the peripheral region 306 can be any value within a range between any of the minimum and maximum values noted above. Furthermore, it will be appreciated the depth 307 of the peripheral region 306 may be an average depth 307 measured from a suitable sampling of multiple pores within the composite body to create a statistically significant average value.

In accordance with other embodiments, the first pore defining composition can have a particular hardness, including, for example, a first hardness (H1) and the composition of the ceramic material can have a second hardness (H2). In certain instances, the first hardness can be not less than the second hardness. More particularly, the first hardness may be different from the second hardness by at least about 1% based on the equation [|(H1-H2)|/(0.5*(H1+H2))]*100. In other embodiments, the difference in hardness between the first hardness and the second hardness can be greater, such as, at least about 2%, at least about 3%, at least about 5%, at least about 8%, at least about 10%, at least about 12%, at least about 15%, at least about 18%, at least about 20%, at least about 22%, at least about 25%, at least about 28%, at least about 30%, at least about 40%, at least about 50% or even at least about 60%. In still another embodiment, the difference between the first hardness and the second hardness may be not greater than about 99%, such as, not greater than about 90%, not greater than about 80%, not greater than about 70%, not greater than about 60%, not greater than about 50%, not greater than about 45%, not greater than about 40%, not greater than about 35%, not greater than about 30%, not greater than about 25%, not greater than about 20%, not greater than about 18%, not greater than about 15%, not greater than about 12%, not greater than about 10% or even not greater than about 8%. It will be appreciated that the difference between the first hardness and the second hardness may be any value within a range between any of the minimum and maximum percentages noted above.

In accordance with an embodiment, the first hardness can be at least about 400 GPa, such as, at least about 430 GPa, at least about 450 GPa, at least about 480 GPa, at least about 500 GPa, at least about 530 GPa, at least about 550 GPa, at least about 580 GPa, at least about 600 GPa, at least about 630 GPa, at least about 650 GPa, at least about 680 GPa, at least about 700 GPa, at least about 730 GPa, at least about 750 GPa, at least about 780 GPa, at least about 800 GPa, at least about 830 GPa, at least about 850 GPa, at least about 880 GPa, at least about 900 GPa, at least about 930 GPa, at least about 950 GPa, at least about 980 GPa, at least about 1000 GPa, at least about 1030 GPa, at least about 1050 GPa, at least about 1080 GPa, at least about 1100 GPa, at least about 1130 GPa, at least about 1150 GPa, at least about 1180 GPa or even at least about 1200 GPa. According to still other embodiments, the first hardness may be not greater than about 1250 GPa, such as, not greater than about 1200 GPa, not greater than about 1150 GPa, not greater than about 1100 GPa, not greater than about 1000 GPa, not greater than about 900 GPa, not greater than about 800 GPa or even not greater than about 700 GPa. It will be appreciated that the first hardness can be within a range between any of the minimum and maximum values noted above.

In accordance with an embodiment, the second hardness can be least about 400 GP, such as, at least about 430 GPa, at least about 450 GPa, at least about 480 GPa, at least about 500 GPa, at least about 530 GPa, at least about 550 GPa, at least about 580 GPa, at least about 600 GPa, at least about 630 GPa, at least about 650 GPa, at least about 680 GPa, at least about 700 GPa, at least about 730 GPa, at least about 750 GPa, at least about 780 GPa or even at least about 800 GPa. According to still other embodiments, the second hardness may be not greater than about 800 GPa, not greater than about 750 GPa, not greater than about 700 GPa, not greater than about 650 GPa, not greater than about 600 GPa or even not greater than about 500 GPa. It will be appreciated that the second hardness can be within a range between any of the minimum and maximum values noted above.

In certain instances, the composition of the ceramic material may include a content of amorphous phase material, polycrystalline phase material, and a combination thereof. In particular instances, the composition of the ceramic material may include a greater content of polycrystalline material as compared to the content of amorphous phase material. In still other embodiments, the content of amorphous material may be greater than the content of crystalline or polycrystalline material.

In certain embodiment, the ceramic material may include not less than about 50 vol % polycrystalline ceramic phase. According to a particular embodiment, the ceramic material can include not less than about 75 vol % polycrystalline ceramic phase, such as, not less than about 80 vol % or even not less than about 90 vol %. According to a particular embodiment, the ceramic material may be comprised essentially of a polycrystalline ceramic phase. The polycrystalline ceramic phase of the ceramic material may be present in an amount between about 60 vol % and about 100 vol %.

Generally, the polycrystalline ceramic phase can include a plurality of crystallites or crystalline grains which have an average size of not less than about 0.05 microns. In one particular embodiment, the average crystallite size may be not less than about 1.0 micron, such as, not less than about 10 microns or even not less than about 20 microns. Still, the average crystallite size may be generally not greater than about 100 microns, such that the average crystallite size may be within a range between about 1.0 micron and 100 microns.

Generally, the composition of the crystallites of the polycrystalline ceramic phase can include silicon dioxide, aluminum oxide or a combination of both. As such, the crystallites of the polycrystalline ceramic phase can include crystals such as, beta-quartz, which can incorporate other metal oxides incorporated in the initial glass powder, such as, for example, Li₂O, K₂O, MgO, ZnO, and Al₂O₃, in a solid solution. In particular, the polycrystalline ceramic phase can include an aluminum silicate phase. According to another particular embodiment, the crystallites of the polycrystalline ceramic phase can include compound oxide crystals, such as, for example, cordierite, enstatite, sapphirine, anorthite, celsian, diopside, spinel, and beta-spodumene, wherein the beta-spodumene in particular may be found in a solid solution.

In addition to the polycrystalline ceramic phase, the ceramic material may also include an amorphous phase. The amorphous phase, like the polycrystalline ceramic phase, can include silicon dioxide and aluminum oxide and additional metal oxide species that may be present within the original glass powder. The amorphous phase may be present in an amount not greater than about 50 vol % of the total volume of the bond material. As such, an amorphous phase may be generally present in a minority amount, such that it may be present in an amount not greater than about 40 vol %, such as, not greater than about 30 vol % or less, such as, not greater than about 15 vol %. According to a particular embodiment, an amorphous phase may be present in an amount of between about 0 vol % to about 40 vol %, and more particularly, within a range between about 5.0 vol % and about 20 vol %.

In certain other embodiments, the first pore defining composition may include a particular content of crystalline material, including, for example, a first crystalline content (C1) and the composition of the ceramic material may include a particular content of crystalline material defined as a second crystalline content (C2). It will be appreciated herein that the measure of content may be according to weight percent (wt %) or volume percent (vol %) based upon the total weight or volume of the composition within the composite body. In certain embodiments, the first crystalline content may be different than the second crystalline content. For example, in certain instances the first crystalline content may be greater than the second crystalline content. In still other embodiments, the first crystalline content may be less than the second crystalline content. In at least one embodiment, the first crystalline content can be different than the second crystalline content by at least about 1% based the equation [(C1−C2)|/(0.5*(C1+C2))]*100%. In other embodiments, the difference in crystalline content between the first crystalline content and second crystalline content may be greater, such as, at least about 2%, at least about 3%, at least about 5%, at least about 10%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80% or even at least about 90%. In still other embodiments, the difference in crystalline content between the first crystalline content and second crystalline content may be not greater than about 99%, such as, not greater than about 90%, not greater than about 80%, not greater than about 70%, not greater than about 60%, not greater than about 50%, not greater than about 40%, not greater than about 30%, not greater than about 20%, not greater than about 10% or even not greater than about 5%. It will be appreciated the difference between the first crystalline content and second crystalline content may be any value within a range between any of the minimum and maximum percentages noted above.

Furthermore, the first pore defining composition may include a particular content of amorphous phase material, defined as a first amorphous content and a composition of the ceramic material may include a particular content of amorphous phase material, defined as a second amorphous content. It will be appreciated herein that the measure of content may be according to weight percent (wt %) or volume percent (vol %) based upon the total weight or volume of the composition within the composite body. In accordance with one embodiment, the first amorphous content can be different than the second amorphous content. In still another embodiment, the first amorphous content may be greater than the second amorphous content. Still, in an alternative embodiment, the first amorphous content can be less than the second amorphous content. According to one aspect, the first amorphous content can be different than the second amorphous content by at least about 1% based upon the equation [|(A1−A2)|/(0.5*(A1+A2))]*100%. In other embodiments, the difference in amorphous content between the first amorphous content and second amorphous content may be greater, such as, at least about 2%, at least about 3%, at least about 5%, at least about 10%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80% or even at least about 90%. In still other embodiments, the difference in amorphous content between the first amorphous content and second amorphous content may be not greater than about 99%, such as, not greater than about 90%, not greater than about 80%, not greater than about 70%, not greater than about 60%, not greater than about 50%, not greater than about 40%, not greater than about 30%, not greater than about 20%, not greater than about 10% or even not greater than about 5%. It will be appreciated the difference between the first amorphous content and second amorphous content may be any value within a range between any of the minimum and maximum percentages noted above.

In at least one aspect, the first pore defining composition may be formed from a mixture having a particular composition to facilitate forming of the composite body in accordance with an embodiment. For example, the first pore defining composition can be formed from a mixture including at least about 30 wt % silicon dioxide (SiO₂) for a total weight of the mixture. In other embodiments, the content of SiO₂ may be greater, such as, at least about 32 wt % or even at least about 34 wt %. Still, in one embodiment, the first composition may be formed from a mixture having not greater than about 50 weight % SiO₂, such as, not greater than about 48 wt % or even not greater than about 46 wt % SiO₂ for the total weight of the first mixture.

Notably, the first pore defining composition may have a content of SiO₂ that may be distinct from the content of SiO₂ in the composition of the ceramic material of the bond material 302. It will be appreciated herein that the measure of content may be according to weight percent (wt %) or volume percent (vol %) based upon the total weight or volume of the composition within the composite body. For example, the first composition can be formed from a mixture including a first content of SiO₂ and the composition of the ceramic material can include a second content of SiO₂ different than the first content. The first content may be less than the second content. In particular instances, the first content (S1) can be less than the second content (S2) by at least about 1% based on of the equation [|(S1−S2)|/(0.5*(S1+S2))]*100%. In at least one embodiment, the first content can be less than the second content by at least about 2%, such as, at least 3%, at least about 4% or even at least about 5%. In still other embodiments, the first content can be less than the second content by not greater than about 40%, such as, not greater than about 35% or even not greater than about 30%. It will be appreciated the difference in first content of SiO₂ and the second content of SiO₂ can be within a range between any of the above minimum and maximum percentages.

In another embodiment, the first pore defining composition can be formed from a mixture comprising a particular content of aluminum oxide (Al₃O₂). For example, the first pore defining composition can be formed from a mixture including at least about 20 wt % Al₃O₂ for a total weight of the mixture. In other embodiments, the content of Al₃O₂ may be greater, such as, at least about 22 wt % or even at least about 23 wt % for a total weight of the mixture. In still another embodiment, the first pore defining composition may include a content of Al₃O₂ of not greater than about 38 wt %, such as, not greater than about 36 wt % or even not greater than about 34 weight % for the total weight of the mixture. It will be appreciated that the first pore defining composition may be formed from a mixture including a content of Al₃O₂ of any value within a range between any of the minimum and maximum percentages noted above.

It will be appreciated that in particular instances, the first pore defining composition can be formed from a mixture having a first content of Al₃O₂ and the composition of the ceramic material making up the bond material 302 may be formed from a mixture having a second content of Al₃O₂, which may be different than the first content. It will be appreciated herein that the measure of content may be according to weight percent (wt %) or volume percent (vol %) based upon the total weight or volume of the composition within the composite body. In another aspect, the first content can be greater than the second content. In still another embodiment, the first content may be greater than the second content by at least about 1% based upon the equation [|(A11−A12)|/(0.5*(A11+A12))]*100%. For at least one embodiment, the first content may be greater than the second content by at least about 2%, such as, at least about 3%, at least about 4% or even at least about 5%. Still, in another embodiment, the first content may be greater than the second content by not greater than about 40%, such as, not greater than about 35% or even not greater than about 30%. It will be appreciated that the first content may be greater than the second content by a percentage within a range between any of the minimum percentages and maximum percentages noted above.

In accordance with another embodiment, the first pore defining composition can be formed from a mixture having a particular content of titanium dioxide (TiO₂). For example, the first pore defining composition may have not greater than about 0.05 wt % TiO₂ for a total weight of the mixture. In other embodiments, the total content of TiO₂ may be less, such as, not greater than about 0.04 wt %, not greater than about 0.02 weigh % or in some instances the first pore defining composition may essentially free of TiO₂.

In certain instances, the first pore defining composition may be formed from a mixture having a first content of TiO₂, the composition of the ceramic material may be formed from a mixture having a second content of TiO₂. It will be appreciated herein that the measure of content may be according to weight percent (wt %) or volume percent (vol %) based upon the total weight or volume of the composition within the composite body. Notably, the first content and second content may be different relative to each other. For example, the first content may be less than the second content. More particularly, the first content can be less than the second content by at least about 1% based upon the equation [|(Ti1−Ti2)|/(0.5*(Ti1+Ti2))]*100%. In at least one embodiment, the first content of TiO₂ can be less than the second content of TiO₂ by at least about 2%, such as, at least about 3%, at least about 10%, at least about 50%, at least about 80% or even at least about 90%.

The first pore defining composition may include a particular content of calcium oxide (CaO). For example, the first pore defining composition may be formed from a mixture including at least about 2 wt % CaO for a total weight of the mixture. In other embodiments, the first pore defining composition may be formed from a mixture including at least about 3 wt %, at least about 5 wt %, at least about 7 wt % or even at least about 8 wt % CaO for a total weight of the mixture. In another non-limiting embodiment the first pore defining composition can be formed from a mixture including not greater than about 20 wt %, such as, not greater than about 18 wt % or even not greater than about 16 wt % CaO. It will be appreciated that the first pore defining composition can be formed from a mixture including a content of CaO within a range between any of the minimum and maximum percentages noted above.

In certain instance, the first pore defining composition may include a content of CaO and SiO₂, and more particularly, the first pore defining composition may be formed from a mixture having a ratio of CaO and SiO₂ (CaO/SiO₂) of at least about 0.1. In other embodiments, the first pore defining composition can be formed from a mixture having a CaO/SiO₂ ratio of at least about 0.3, such as, at least about 0.15 or even at least about 0.17. In still another non-limiting embodiment, the first pore defining composition may be formed from mixture having CaO/SiO₂ ratio that may be not greater than about 0.7, such as, not greater than about 0.6, not greater than about 0.5 or even not greater than about 0.45. It will be appreciated the first pore defining composition can be formed from a mixture having a CaO/SiO₂ ratio of any value within a range between any of the minimum and maximum values noted above.

Furthermore, the first pore defining composition may be formed from a mixture having a particular content of CaO, defined by a first content of CaO and the composition of the ceramic material including the bond material 302 can be formed from a mixture having a particular second content of CaO. It will be appreciated herein that the measure of content may be according to weight percent (wt %) or volume percent (vol %) based upon the total weight or volume of the composition within the composite body. The first content of CaO may be different than the second content of CaO. For example, the first content may be greater than the second content. More particularly, the first content may be greater than the second content by at least about 1% based upon the equation [|(Ca1−Ca2)|/(0.5*(Ca1+Ca2))]*100%. It will be appreciated that in other embodiments, the first content of CaO may be greater than the second content of CaO by at least about 2%, such as, at least about 3%, at least about 4%, at least about 5%, at least about 10% or even at least about 15%. Still, in other non-limiting embodiments, the first content of CaO may be greater than the second content of CaO by not greater than about 99%, such as, not greater than about 95%. It will be appreciated that the first content of CaO may be greater than the second content of CaO by a percent of any value within a range between any of the minimum and maximum percentages noted above.

In another embodiment, the first pore defining composition may include a particular content of cesium oxide (Cs₂O). For example, the first pore defining composition may be formed from a mixture including at least about 2wt % Cs₂O for a total weight of the mixture. In other embodiments, the first pore defining composition may be formed from a mixture including at least about 3 wt %, such as, at least 5 wt % or even at least about 7 wt % Cs₂O for the total weight of the mixture. Yet, in other instances, the first pore defining composition may be formed from a mixture including not greater than about 22 wt %, such as, not greater than about 20 wt % or even not greater than about 18 wt % Cs₂O for the total weight of the mixture. It will be appreciated that the first pore defining composition can be formed from a mixture having a content of Cs₂O of any value within a range between any of minimum and maximum percentages noted above.

In certain embodiments, the first pore defining composition can be formed from a mixture having a Cs₂O/SiO₂ratio of at least about 0.1 based upon the wt % of the respective components in the mixture used to form the first pore defining composition. In other embodiments, the first pore defining composition can be formed from a mixture having a Cs₂O/SiO₂ ratio of at least about 0.13, such as, at least about 0.15. In other embodiments, the composition may be formed from a mixture having a Cs₂O/SiO₂ ratio of not greater than about 0.7, such as, not greater than about 0.6 or even not greater than about 0.55. It will be appreciated that the first pore defining composition can be formed from a mixture having a Cs₂O/SiO₂ratio of any value within a range between any of the minimum and maximum values noted above.

In at least one embodiment, the first pore defining composition can be formed from a mixture having a first content of Cs₂O and the composition of the ceramic material can be formed from a mixture having a second content of Cs₂O. It will be appreciated herein that the measure of content may be according to weight percent (wt %) or volume percent (vol %) based upon the total weight or volume of the composition within the composite body. In particular instances, the first content of Cs₂O can be different than the second content of Cs₂O. More particularly, the first content may be greater than the second content. For example, the first content of Cs₂O can be greater than the second content of Cs₂O by at least about 1% based upon the equation [|(Cs1−Cs2)|/(0.5*(Cs1+Cs2))]*100%. For another embodiment, the first content of Cs₂O can be greater than the second of Cs₂O by at least about 2%, such as, at least about 3%, at least about 4%, at least about 5%, at least about 10%, at least about 15% or even at least about 20%. Still, the first content may be greater than the second content by not greater than about 90% or even not greater than about 95%. It will be appreciated that the first content may be different than the second content by any value within a range between any of the minimum and maximum values noted above.

In one aspect, the first pore defining composition may include a particular content of barium oxide (BaO). For example, the first pore defining composition may be formed from a mixture including at least about 2 wt %, such as, at least about 3 wt %, at least about 5 wt % or even at least about 7wt % BaO for a total weight of the mixture. In other embodiments, the first pore defining composition can be formed from a mixture having not greater than about 26 wt %, such as, not greater than about 24 wt % or even not greater than about 22 wt % BaO for the total weight of the mixture. It will be appreciated that the first pore defining composition can be formed from a mixture having a content of BaO of any value within a range between any of the minimum and maximum values noted above.

In another aspect, the first pore defining composition may be formed from a mixture having a particular ratio of BaO to SiO₂, for example, a BaO/SiO₂ratio of at least about 0.1. In other instances, the first pore defining composition may be formed from a mixture having a BaO/SiO₂ ratio of at least about 0.15, such as, at least about 0.2. Still, in another embodiment, the first pore defining composition may be formed from a mixture having BaO/SiO₂ ratio of not greater than about 0.8, such as, not greater than about 0.7 or even not greater than about 0.68. It will be appreciated that the first pore defining composition can be formed from a mixture having a BaO/SiO₂ ratio of any value within a range between any of the minimum and maximum values noted about.

In certain instances, the first pore defining composition can include a first content of BaO and the composition of the ceramic material may be defined by a second content of BaO. It will be appreciated herein that the measure of content may be according to weight percent (wt %) or volume percent (vol %) based upon the total weight or volume of the composition within the composite body. The second content of BaO may be different than the first content of BaO. More particularly, the first content of BaO can be greater than the second content of BaO. In one embodiment, the first content of BaO can be greater than the second content of BaO by at least about 1% based upon the equation [|(Ba1−Ba2)|/(0.5*(Ba1+Ba2))]*100%. For another embodiment, the first content of BaO may be greater than the second content by at least about 2%, such as, at least about 3%, at least about 4%, at least about 5%, at least about 10% or even at least about 15%. Still, in one non-limiting embodiment the first content of BaO can be greater than the second content of BaO by not the greater than about 99%, such as, not greater than about 95. It will be appreciated that the first content of BaO can be different than the second content of BaO by any value within a range between any of the minimum and maximum values noted above.

Furthermore, in another aspect, the first pore defining composition may be formed from a mixture including a particular content of magnesium oxide (MgO). For example, the first pore defining composition may be formed from a mixture including at least about 2 wt %, such as, at least about 3 wt %, at least about 5 wt % or even at least about 7 wt % MgO for a total weight of the mixture. In other instances, the first pore defining composition may be formed from a mixture including not greater than about 20 wt %, such as, not greater than about 18 wt % or even not greater than about 16 wt % MgO for a total weight of the mixture. It will be appreciated that the first pore defining composition can include a content of MgO within a range between any of the minimum and maximum percentages noted above.

In accordance with an embodiment, the first pore defining composition can be formed from a mixture having a MgO/SiO₂ ratio of at least about 0.1% wherein the content of MgO and SiO₂ may be measured in wt % for the total weight of the mixture. In other instance, the first pore defining composition may be formed from a mixture MgO/SiO₂ ratio of at least about 0.13, such as, at least about 0.15. Still, the first pore defining composition may be formed from a mixture having a MgO/SiO₂ ratio of not greater than about 0.7, such as, not greater than about 0.6, not greater than about 0.5 or even not greater than about 0.45. It will be appreciated the first pore defining composition may be formed from a mixture having a MgO/SiO₂ ratio within a range between any of the minimum and maximum values noted above.

In accordance with an embodiment, the first pore defining composition can include a particular content of additives, including for example oxide-based additives such as, MgO, CaO, BaO, ZrO₂, Cs₂O. In particular embodiments, the first pore defining composition may include only one additive of the group MgO and CaO. For example, the first pore defining composition may be formed from a mixture including MgO or alternatively CaO. In at least one embodiment, the first pore defining composition may be formed from a mixture that does not include both MgO and CaO. In another embodiment, the first pore defining composition may be formed from a mixture that can include one of a first group of additives that can consist essentially of CaO and BaO. Alternatively, the first pore defining composition can include a second group of additives including, and more particularly, consisting essentially of MgO. For example, the first pore defining composition may be formed from either the first group of additives or the second group of additives, in particularly need not necessarily include both the first group of additives and the second group of additives.

In more particular instances, the first pore defining composition may include only one of a first group of additives including, more particularly, consisting essentially of CaO, BaO, and ZrO₂. Alternatively, the first pore defining composition may include only a second group of additives including, more particularly, consisting essentially of MgO and Cs₂O. It will be appreciated that in certain instances, the first pore defining composition may include only one of the first group of additives or the second group of additives, but not both the first group and second group of additives. Furthermore, it will be appreciated that the additives may not necessarily include other oxide species such as, SiO₂, AlO₂ and the like.

In accordance with an embodiment, the first pore defining composition may be formed from a mixture including a particular content of boron oxide (B₂O). For example, the first pore defining composition may be formed from a mixture including not greater than about 7 wt %, such as, not greater than about 6 wt %, not greater than about 5 wt % or even not greater than about 4 wt % B₂O for a total weight of the mixture. In at least one embodiment, the first pore defining composition may be formed from a mixture including at least about 0.05 wt % B₂O. it will be appreciated that the first pore defining composition may be formed from a mixture including a content of B₂O of any value within a range of any of the minimum and maximum percentages notes above.

In another embodiment, the first pore defining composition may include a particular content of ZrO₂. For example, the first pore defining composition may be formed from a mixture including at least about 1 wt %, such as, at least about 1.5 wt %, at least about 2 wt % or even at least about 3 wt % ZrO₂ for a total weight of the mixture. In another non-limiting embodiment, the first pore defining composition may be formed from a mixture including not greater than about 10 wt %, such as, not greater than about 8 wt % or even not greater than about 6 wt % ZrO₂ for a total weight of the mixture. It will be appreciated that the first pore defining composition may be formed from a mixture including a content of ZrO₂ of any value within a range between any of the minimum and maximum percentages noted above.

According to one aspect, the first pore defining composition may be formed from a mixture including a first content of ZrO₂ and the composition of the ceramic material including the bond material 302 may be formed from a second content of ZrO₂. It will be appreciated herein that the measure of content may be according to weight percent (wt %) or volume percent (vol %) based upon the total weight or volume of the composition within the composite body. The first content of ZrO₂ and the second content of ZrO₂ may be different with respect to each other. Furthermore, it will be appreciated that the content of ZrO₂ may be measured as the wt % of ZrO₂. In accordance with an embodiment, the first content may be greater than the second content, and more particularly, the first content may be greater than the second content by at least about 1% based upon the equation [|(Zr1−Zr2)|/(0.5*(Zr1+Zr2))]*100%. In one embodiment, the first content of ZrO₂ can be greater than the second content of ZrO₂ by at least about 2%, such as, at least about 3%, at least about 4%, at least about 5%, at least about 10% or even at least about 15%. Still, in another non-limiting embodiment, the first content of ZrO₂ can be greater than the second content of ZrO₂ by not greater than about 99%, such as, not greater than about 95%. It will be appreciated that in certain instances, the first content of ZrO₂ can be greater than the second content of ZrO₂ by any value within a range between any of the minimum and maximum percentages noted above.

In certain instances, the first pore defining composition may be formed from a mixture having a particular content of sodium oxide (Na₂O). For example, the first pore defining composition may be formed from a mixture of having a first content of Na₂O and the composition of the ceramic material making up the bond material may be formed from a mixture having a second content of Na₂O. It will be appreciated herein that the measure of content may be according to weight percent (wt %) or volume percent (vol %) based upon the total weight or volume of the composition within the composite body. The first content and second content of Na₂O may be different with respect to each other. More particularly, the first content of Na₂O may be less than the second content of Na₂O. For example, in one embodiment, the first content of Na₂O can be less than the second content of Na₂O by at least 1% based on the equation [|(Na1−Na2)|/(0.5*(Na1+Na2))]*100%. In another embodiment, the first content of Na₂O can be less than the second content of Na₂O by at least about 2%, such as, at least about 3%, at least about 4%, at least about 5%, at least about 10% or even at least about 15%. It will be appreciated, however that in one non-limiting embodiment, the first content of Na₂O can be less than the second content of Na₂O by not greater than about 99% or even not greater than about 95%. It will be appreciated that the first content can be less than the second content of Na₂O by any value within a range between any of the minimum and maximum percentages noted above.

In one aspect, the first pore defining composition may be formed from a mixture having a particular content of Na₂O. For example, in one embodiment, the first pore defining composition may be formed from a mixture having a content of Na₂O of not great than about 5 wt %, such as, not greater than about 4 wt %, not greater than about 2 wt % or even not greater than about 1 wt % for the total weight of the mixture. In another embodiment, the first pore defining composition may be formed from a mixture that may be essentially free of Na₂O.

In another embodiment, the first pore defining composition may be formed from a mixture having a particular content of lithium oxide (Li₂O). For example, the first pore defining composition may be formed from a mixture having a first content of Li₂O and the composition of the ceramic material making up the bond material 302 may be formed from a mixture having a second content of Li₂O based upon wt % of the materials in the mixture. In one aspect, the first content of Li₂O can be different than the second content of Li₂O. More particularly, the first content of Li₂O may be less than the second content of Li₂O. For example, the first content of Li₂O can be less than the second content of Li₂O by at least 1% based upon the equation [|(Li1−Li2)|/(0.5*(Li1+Li2))]*100%. In another embodiment, the first content of Li₂O can be less than the second content of Li₂O by at least about 2%, such as, at least about 3%, at least about 4%, at least about 5%, at least about 10% or even at least about 15%. Still, in one non-limiting embodiment, the first content of the Li₂O can be less than the second content of Li₂O by not greater than about 99%, such as, not greater than about 95%. It will be appreciated that the first content of Li₂O can be less than the second content of Li₂O by any value within a range between any of the minimum and maximum values noted above.

In accordance with an embodiment, the first pore defining composition can be formed from a mixture having a particular content of Li₂O. In one particular embodiment, the first pore defining composition can be formed from a mixture that may be essentially free of Li₂O.

In another embodiment, the first pore defining composition may be formed from a mixture having a particular content of iron oxide (Fe₂O₃). For example, the first pore defining composition may be formed from a mixture having a first content of Fe₂O₃ and the composition of the ceramic material making up the bond material 302 may be formed from a mixture having a second content of Fe₂O₃ based upon the wt % of Fe₂O₃ in the mixture. For at least one embodiment, the first content of Fe₂O₃ may be different than the second content of Fe₂O₃. More particularly, the first content of Fe₂O₃ may be less than the second content of Fe₂O₃. In one particular embodiment, the first content of Fe₂O₃ can be less than the second content of Fe₂O₃ by at least about 1% based upon the equation [|(Fe1−Fe2)|/(0.5*(Fe1+Fe2))]*100%. In accordance with one embodiment, the first content of Fe₂O₃ can be less than the second content of Fe₂O₃ by at least about 2%, such as, at least about 3% at least about 4%, at least about 5%, at least about 10% or even at least about 15%. In still another non-limiting embodiment, the first content of Fe₂O₃ can be less than the second content of Fe₂O₃ by not greater than about 99% or even not greater than about 95%. It will be appreciated that the first content of Fe₂O₃ may be less than the second content of Fe₂O₃ by a percentage within a range between any of the minimum and maximum percentages noted above.

In accordance with one particular embodiment, the first pore defining composition can be formed from a mixture having a particular content of Fe₂O₃. For example, in certain instances, the first pore defining composition may be formed from a mixture that may be essentially free of Fe₂O₃.

The first pore defining composition may include a particular content of phosphorous oxide (P₂O₃). For example, in one embodiment, the first pore defining composition may be formed from a mixture having a first content of P₂O₃ of not greater than about 5 wt %, such as, not greater than about 4 wt %, not greater than about 2 wt % or even not greater than about 1 wt % for a total weight of the mixture. In one particular embodiment, the first pore defining composition may be formed from a mixture that may be essentially free of P₂O₃.

In the final formed composite body, the abrasive grains generally comprise not less than about 25 vol % of the total volume of the composite body. According to embodiments, the abrasive grains generally comprise not less than about 35 vol %, such as, not less than about 45 vol % or even not less than about 50 vol % of the total volume of the final formed composite body. According to one particular embodiment, the abrasive grains comprise between about 35 vol % and about 60 vol % of the total volume of the final formed abrasive article.

Generally, the bond material may be present in an amount of not greater than about 60 vol % of the total volume of the final formed composite body. As such, the bonded abrasive generally can include not greater than about 50 vol % bond material, such as, not greater than about 40 vol % or even not greater than about 30 vol %. Accordingly, the bond material may be generally present within an amount of between about 10 vol % and about 30 vol % of the total volume of the final formed composite body.

It will be appreciated that the bond material can include those compounds and particularly the ratio of the compounds within the initial bond material precursor powder and glass powder as described above. That is, the bond material comprises substantially the same composition as that of the bond material precursor power and glass powder, notably this can include metal oxide compounds, particularly complex metal oxide compounds, and more particularly, silicate-based compositions, such as, for example, an aluminum silicate, MAS, LAS, BAS, CMAS or CBAS composition.

Moreover, the thermal expansion coefficient of the bond material may be low, such as, not greater than about 80×10⁻⁷/K⁻¹. According to a particular embodiment, the bond material has a thermal expansion coefficient not greater than about 60×10⁻⁷/K⁻¹, such as, not greater than about 50×10⁻⁷/K⁻¹ or even not greater than about 40×10⁻⁷/K⁻¹. As such, the thermal expansion coefficient of the bond material may be within a range of between about 10×10⁻/K⁻¹ and about 80×10⁻⁷/K⁻¹.

The post-heating polycrystalline bond material generally has a flexural strength of not less than about 80 MPa. In other embodiments, the flexural strength of the bond material may be greater, such as, not less than about 90 MPa, not less than about 100 MPa or in some instances, not less than about 110 MPa. According to a particular embodiment, the flexural strength of the bond material may be within a range of between about 90 MPa and about 150 MPa.

In addition to such characteristics, the post-heating polycrystalline bond material generally has a toughness of not less than about 0.8 MPa m^(1/2). In other embodiments, the toughness of the bond material can be greater, such as, not less than about 1.5 MPa m^(1/2) or even not less than about 2.0 MPa m^(1/2).

In reference to properties of the composite body, generally the formed composite body has a modulus of rupture (MOR) of not less than about 20 MPa. However, the MOR can be greater, such as, not less than about 30 MPa or not less than about 40 MPa, such as, not less than about 50 MPa or even not less than about 60 MPa. In one particular embodiment, the MOR of the composite body may be not less than about 70 MPa, and may be within a range of between about 50 MPa and about 150 MPa.

In further reference to properties of the composite bodies, according to one embodiment, the abrasive articles have a modulus of elasticity (MOE) of not less than about 40 GPa. In another embodiment, the MOE may be not less than about 80 GPa, such as, not less than about 100 GPa, and even not less than about 140 GPa. Generally, the MOE of the composite body may be within a range of between about 40 GPa and about 200 GPa, and particularly within a range between about 60 GPa and about 140 GPa.

ITEMS

Item 1. A composite body comprising:

a bond material comprising a ceramic material; and

a pore within the ceramic material;

wherein a region of the bond material at a surface of the pore defines a first pore defining composition distinct from a composition of the ceramic material, the first pore defining composition having a melting point not less than a melting point of the composition of the ceramic material.

Item 2. A composite body comprising:

a bond material comprising a ceramic material; and

a pore within the ceramic material of the bond material;

wherein a peripheral region of the bond material including a portion of a surface defining the pore and extending for a depth into the bond material has a first pore defining composition distinct from a composition of the ceramic material, the first pore defining composition having a melting point not less than a melting point of the composition of the ceramic material.

Item 3. A composite body comprising:

a bond material comprising a ceramic material; and

a pore within the ceramic material;

wherein a region of the bond material at a surface of the pore defines a first pore defining composition distinct from a composition of the ceramic material; and

wherein the first pore defining composition has a first melting point (Tm1) and the composition of the ceramic material has a second melting point (Tm2), and a differential melting point between the first melting point and the second melting point defined as [Tm1-Tm2] of at least about 0.5° C. and not greater than about 1000° C.

Item 4. A composite body comprising:

a bond material comprising a ceramic material; and

a pore within the ceramic material;

wherein a region of the bond material at a surface of the pore defines a first pore defining composition distinct from a composition of the ceramic material;

wherein the first composition has a first hardness (H1) and the composition of the ceramic material has a second hardness (H2); and

wherein the first hardness is not less than the second hardness.

Item 5. The composite body of any one of items 1, 2, 3 and 4, wherein the ceramic material comprises a material selected from the group consisting of an amorphous phase, a polycrystalline phase, and a combination thereof.

Item 6. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition comprises a first crystalline content (C1) and the ceramic material comprises a second crystalline content (C2), wherein the first crystalline content is different than the second crystalline content, wherein the first crystalline content is greater than the second crystalline content, wherein the first crystalline content is less than the second crystalline content, wherein the first crystalline content is different than the second crystalline content by at least about 1% based on the equation [|(C1−C2)|/(0.5*(C1+C2))]*100%.

Item 7. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition comprises a first amorphous content (A1) and the ceramic material comprises a second amorphous content (A2), wherein the first amorphous content is different than the second amorphous content, wherein the first amorphous content is greater than the second amorphous content, wherein the first amorphous content is less than the second amorphous content, wherein the first amorphous content is different than the second amorphous content by at least about 1% based on the equation [|(A1−A2)|/(0.5*(A1+A2))]*100%.

Item 8. The composite body of any one of items 1, 2, and 4, wherein the first pore defining composition has a first melting point (Tm1) and the composition of the ceramic material has a second melting point (Tm2), and a differential melting point between the first melting point and the second melting point defined as [Tm1-Tm2] is at least about 0.5° C. and not greater than about 1000° C.

Item 9. The composite body of any one of items 3and 8, wherein the differential melting point is at least about 1° C., at least about 2° C., at least about 3° C., at least about 4° C., at least about 5° C., at least about 6° C., at least about 7° C., at least about 8° C., at least about 9° C., at least about 10° C., at least about 12° C., at least about 15° C., at least about 18° C., at least about 20° C., at least about 25° C., at least about 30° C., at least about 35° C., at least about 40° C., at least about 45° C., at least about 50° C., at least about 55° C., at least about 100° C., at least about 200° C., at least about 300° C., at least about 400° C., at least about 500° C., at least about 600° C., at least about 700° C., at least about 800° C., at least about 900° C. and wherein the differential melting point is not greater than about 1000° C., not greater than about 900° C., not greater than about 800° C., not greater than about 700° C., not greater than about 600° C., not greater than about 500° C., not greater than about 400° C., not greater than about 300° C., not greater than about 200, not greater than about 190° C., not greater than about 180° C., not greater than about 170° C., not greater than about 160° C., not greater than about 150° C., not greater than about 140° C., not greater than about 130° C., not greater than about 120° C., not greater than about 110° C., not greater than about 100° C., not greater than about 90° C., not greater than about 80° C., not greater than about 70° C., not greater than about 60° C., not greater than about 50° C.

Item 10. The composite body of any one of items 3 and 8, wherein the first pore defining composition comprises a melting point of at least about 1100° C., at least about 1200° C., at least about 1300° C., at least about 1350° C., and wherein the first pore defining composition comprises a melting point of not greater than about 1800° C., not greater than about 1700° C., not greater than about 1600° C.

Item 11. The composite body of any one of items 3 and 8, wherein the composition of the ceramic material comprises a melting point of at least about 1000° C., at least about 1100° C., at least about 1200° C., at least about 1300° C., and wherein the composition of the ceramic material comprises a melting point of not greater than about 1700° C., not greater than about 1600° C., not greater than about 1500° C.

Item 12. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition has a first melting point (Tm1) and the composition of the ceramic material has a second melting point (Tm2), and a differential melting point percentage defined by the equation [|(Tm1−Tm2)|/(0.5*(Tm1+Tm2))]*100% is at least about 1%, at least about 2%, at least about 3%, at least about 5%, at least about 8%, at least about 10%, at least about 12%, at least about 15%, at least about 18%, at least about 20%, at least about 22%, at least about 25%, at least about 28%, at least about 30%.

Item 13. The composite body of item 12, wherein the differential melting point percentage defined by the equation [|(Tm1−Tm2)|/(0.5*(Tm1+Tm2))]*100% is not greater than about 99%, not greater than about 90%, not greater than about 80%, not greater than about 70%, not greater than about 60%, not greater than about 50%, not greater than about 45%, not greater than about 40%, not greater than about 35%, not greater than about 30%, not greater than about 25%, not greater than about 20%, not greater than about 18%, not greater than about 15%, not greater than about 12%, not greater than about 10%, not greater than about 8%.

Item 14. The composite body of any one of items 1, 3, and 4, wherein a peripheral region of the bond material defined by at least a portion of a surface defining the opening and extending for a depth into the bond material has a first pore defining composition distinct from a composition of the ceramic material, the first pore defining composition having a melting point not less than a melting point of the composition of the ceramic material.

Item 15. The composite body of any one of items 2 and 14, wherein the depth is not greater than a diameter of the pore, wherein the depth is greater than a diameter of the pore, wherein the depth is not greater than about 200 microns, not greater than about 180 microns, not greater than about 150 microns, not greater than about 100 microns, and wherein the depth is at least about 1 micron, at least about 3 microns, at least about 5 microns, at least about 10 microns.

Item 16. The composite body of any one of items 1, 2, and 3, wherein the first pore defining composition has a first hardness (H1) and the composition of the ceramic material has a second hardness (H2), and wherein first hardness is not less than the second hardness.

Item 17. The composite body of any one of items 4 and 16, wherein the first hardness is different from the second hardness by at least about 1% based on the equation [|(H1−H2)|/(0.5*(H1+H2))]*100%, wherein the difference in hardness between the first hardness and second hardness is at least about 2%, at least about 3%, at least about 5%, at least about 8%, at least about 10%, at least about 12%, at least about 15%, at least about 18%, at least about 20%, at least about 22%, at least about 25%, at least about 28%, at least about 30%, at least about 40%, at least about 50%, at least about 60%.

Item 18. The composite body of item 17, wherein the first hardness is different from the second hardness by not greater than about 99%, not greater than about 90%, not greater than about 80%, not greater than about 70%, not greater than about 60%, not greater than about 50%, not greater than about 45%, not greater than about 40%, not greater than about 35%, not greater than about 30%, not greater than about 25%, not greater than about 20%, not greater than about 18%, not greater than about 15%, not greater than about 12%, not greater than about 10%, not greater than about 8%.

Item 19. The composite body of any one of items 4 and 16, wherein the first hardness is at least about 400 GPa, at least about 430 GPa, at least about 450 GPa, at least about 480 GPa, at least about 500 GPa, at least about 530 GPa, at least about 550 GPa, at least about 580 GPa, at least about 600 GPa, at least about 630 GPa, at least about 650 GPa, at least about 680 GPa, at least about 700 GPa, at least about 730 GPa, at least about 750 GPa, at least about 780 GPa, at least about 800 GPa, at least about 830 GPa, at least about 850 GPa, at least about 880 GPa, at least about 900 GPa, at least about 930 GPa, at least about 950 GPa, at least about 980 GPa, at least about 1000 GPa, at least about 1030 GPa, at least about 1050 GPa, at least about 1080 GPa, at least about 1100 GPa, at least about 1130 GPa, at least about 1150 GPa, at least about 1180 GPa, at least about 1200 GPa, not greater than about 1250 GPa, not greater than about 1200 GPa, not greater than about 1150 GPa, not greater than about 1100 GPa, not greater than about 1000 GPa, not greater than about 900 GPa, not greater than about 800 GPa, not greater than about 700 GPa.

Item 20. The composite body of any one of items 4 and 16, wherein the second hardness is at least about 400 GPa, at least about 430 GPa, at least about 450 GPa, at least about 480 GPa, at least about 500 GPa, at least about 530 GPa, at least about 550 GPa, at least about 580 GPa, at least about 600 GPa, at least about 630 GPa, at least about 650 GPa, at least about 680 GPa, at least about 700 GPa, at least about 730 GPa, at least about 750 GPa, at least about 780 GPa, at least about 800 GPa, at least about 830 GPa, at least about 850 GPa, at least about 880 GPa, at least about 900 GPa, at least about 930 GPa, at least about 950 GPa, at least about 980 GPa, at least about 1000 GPa, at least about 1030 GPa, at least about 1050 GPa, at least about 1080 GPa, at least about 1100 GPa, at least about 1130 GPa, at least about 1150 GPa, at least about 1180 GPa, at least about 1200 GPa, not greater than about 1250 GPa, not greater than about 1200 GPa, not greater than about 1150 GPa, not greater than about 1100 GPa, not greater than about 1000 GPa, not greater than about 900 GPa, not greater than about 800 GPa, not greater than about 700 GPa.

Item 21. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition comprises a crystalline phase selected from the group consisting of cordierite, indialite, enstatite, sapphirine, anorthite, celsian, diopside, spinel, beta-spodumene, and a combination thereof.

Item 22. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition is formed from a mixture comprising at least about 30 wt % and not greater than about 50 wt % silicon dioxide (SiO2) for a total weight of the mixture, at least about 32 wt %, at least about 34 wt %, and not greater than about 48 wt %, not greater than about 46 wt %.

Item 23. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition is formed from a mixture comprising a first content (S1) of silicon dioxide (SiO2) and the composition of the ceramic material comprises a second content (S2) of silicon dioxide different than the first content, wherein the first content is less than the second content, wherein the first content is less than the second content by at least about 1% based on the equation [|(S1−S2)|/(0.5*(S1+S2))]*100%, at least about 2%, at least about 3%, at least about 4%, and not greater than about 40%, not greater than about 35%, not greater than about 30%.

Item 24. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition is formed from a mixture comprising at least about 20 wt % and not greater than about 38 wt % aluminum oxide (Al3O2) for a total weight of the mixture, at least about 22 wt %, and not greater than about 36 wt %, not greater than about 34 wt %.

Item 25. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition is formed from a mixture comprising a first content (A11) of aluminum oxide (Al2O3) and the composition of the ceramic material comprises a second content (A12) of aluminum oxide different than the first content, wherein the first content is greater than the second content, wherein the first content is greater than the second content by at least about 1% based on the equation [|(A11−A12)|/(0.5*(A11+A12))]*100%, at least about 2%, at least about 3%, at least about 4%, and not greater than about 40%, not greater than about 35%, not greater than about 30%.

Item 26. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition is formed from a mixture comprising not greater than about 0.05 wt % titanium dioxide (TiO2) for a total weight of the mixture, not greater than about 0.04 wt %, not greater than about 0.02 wt %, wherein the first composition is essentially free of titanium dioxide.

Item 27. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition is formed from a mixture comprising a first content (Ti1) of titanium dioxide (TiO2) and the composition of the ceramic material comprises a second content (Ti2) of titanium dioxide different than the first content, wherein the first content is less than the second content, wherein the first content is less than the second content by at least about 1% based on the equation [|(Ti1−Ti2)|/(0.5*(Ti1+Ti2))]*100%, at least about 2%, at least about 3%, at least about 10%, at least about 50%, at least about 80%, at least about 90%.

Item 28. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition is formed from a mixture comprising at least about 2 wt % calcium oxide (CaO) for a total weight of the mixture, at least about 3 wt %, at least about 5 wt %, at least about 7 wt %, and not greater than about 20 wt %, not greater than about 18 wt %, not greater than about 16 wt %.

Item 29. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition comprises calcium oxide (CaO) and silicon dioxide (SiO2), and wherein first pore defining composition is formed from a mixture having a CaO/SiO2 ratio of at least about 0.1, at least about 0.13, at least about 0.15, and wherein the first pore defining composition is formed from a mixture having a CaO/SiO2 ratio of not greater than about 0.7, not greater than about 0.6, not greater than about 0.5, not greater than about 0.45.

Item 30. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition is formed from a mixture comprising a first content (Ca1) of calcium oxide (CaO) and the composition of the ceramic material comprises a second content (Ca2) of calcium oxide different than the first content, wherein the first content is greater than the second content, wherein the first content is greater than the second content by at least about 1% based on the equation [|(Ca1−Ca2)|/(0.5*(Ca1+Ca2))]*100%, at least about 2%, at least about 3%, at least about 4%, at least about 5%, at least about 10%, at least about 15%, and not greater than about 99%, not greater than about 95%.

Item 31. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition is formed from a mixture comprising at least about 2 wt % cesium oxide (Cs2O) for a total weight of the mixture, at least about 3wt %, at least about 5 wt %, at least about 7 wt %, and not greater than about 22 wt %, not greater than about 20 wt %, not greater than about 18 wt %.

Item 32. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition comprises cesium oxide (Cs2O) and silicon dioxide (SiO2), and wherein first pore defining composition is formed from a mixture having a Cs2O/SiO2 ratio of at least about 0.1, at least about 0.13, at least about 0.15, and wherein the composition is formed from a mixture having a Cs2O/SiO2 ratio of not greater than about 0.7, not greater than about 0.6, not greater than about 0.55.

Item 33. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition is formed from a mixture comprising a first content (Cs1) of cesium oxide (Cs2O) and the composition of the ceramic material comprises a second content (Cs2) of cesium oxide different than the first content, wherein the first content is greater than the second content, wherein the first content is greater than the second content by at least about 1% based on the equation [|(Cs1−Cs2)|/(0.5*(Cs1+Cs2))]*100%, at least about 2%, at least about 3%, at least about 4%, at least about 5%, at least about 10%, at least about 15%, and not greater than about 99%.

Item 34. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition is formed from a mixture comprising at least about 2 wt % barium oxide (BaO) for a total weight of the mixture, at least about 3 wt %, at least about 5 wt %, at least about 7 wt %, and not greater than about 26 wt %, not greater than about 24 wt %, not greater than about 22 wt %.

Item 35. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition comprises barium oxide (BaO) and silicon dioxide (SiO2), and wherein first pore defining composition is formed from a mixture having a BaO/SiO2 ratio of at least about 0.1, at least about 0.15, at least about 0.2, and wherein the composition is formed from a mixture having a BaO/SiO2 ratio of not greater than about 0.8, not greater than about 0.7, not greater than about 0.68.

Item 36. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition is formed from a mixture comprising a first content (Ba1) of barium oxide (BaO) and the composition of the ceramic material comprises a second content (Ba2) of barium oxide different than the first content, wherein the first content is greater than the second content, wherein the first content is greater than the second content by at least about 1% based on the equation [|(Ba1−Ba2)|/(0.5*(Ba1+Ba2))]*100%, at least about 2%, at least about 3%, at least about 4%, at least about 5%, at least about 10%, at least about 15%, and not greater than about 99%, not greater than about 95%.

Item 37. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition is formed from a mixture comprising at least about 2 wt % magnesium oxide (MgO) for a total weight of the mixture, at least about 3 wt %, at least about 5 wt %, at least about 7 wt %, and not greater than about 20 wt %, not greater than about 18 wt %, not greater than about 16 wt %.

Item 38. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition comprises magnesium oxide (MgO) and silicon dioxide (SiO2), and wherein first pore defining composition is formed from a mixture having a MgO/SiO2 ratio of at least about 0.1, at least about 0.13, at least about 0.15, and wherein the first pore defining composition is formed from a mixture having a MgO/SiO2 ratio of not greater than about 0.7, not greater than about 0.6, not greater than about 0.5, not greater than about 0.45.

Item 39. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition comprises only one additive selected from the group of additives consisting of magnesium oxide (MgO) and calcium oxide (CaO).

Item 40. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition comprises only one of:

i) a first group of additives including calcium oxide (CaO) and barium oxide (BaO); and

ii) a second group of additives including magnesium oxide (MgO).

Item 41. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition comprises only one of:

i) a first group of additives including calcium oxide (CaO), barium oxide (BaO), and zirconia oxide (ZrO₂); and

ii) a second group of additives including magnesium oxide (MgO) and cesium oxide (C_(S)2O).

Item 42. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition is formed from a mixture comprising not greater than about 7 wt % boron oxide (B2O3) for a total weight of the mixture, and not greater than about 6 wt %, not greater than about 5 wt %, and at least about 0.05 wt %.

Item 43. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition is formed from a mixture comprising at least about 1 wt % zirconium oxide (Zr2O) for a total weight of the mixture, at least about 1.5 wt %, at least about 2 wt %, at least about 3 wt %, and not greater than about 10 wt %, not greater than about 8 wt %, not greater than about 6 wt %.

Item 44. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition is formed from a mixture comprising a first content (Zr1) of zirconium oxide (Zr2O) and the composition of the ceramic material comprises a second content (Zr2) of zirconium oxide different than the first content, wherein the first content is greater than the second content, wherein the first content is greater than the second content by at least about 1% based on the equation [|(Zr1−Zr2)|/(0.5*(Zr1+Zr2))]*100%, at least about 2%, at least about 3%, at least about 4%, at least about 5%, at least about 10%, at least about 15%, and not greater than about 99%, not greater than about 95%.

Item 45. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition is formed from a mixture comprising a first content (Na1) of sodium oxide (Na₂O) and the composition of the ceramic material comprises a second content (Na2) of sodium oxide different than the first content, wherein the first content is less than the second content, wherein the first content is less than the second content by at least about 1% based on the equation [|(Na1−Na2)|/(9.5*(Na1+Na2))]*100%, at least about 2%, at least about 3%, at least about 4%, at least about 5%, at least about 10%, at least about 15%, and not greater than about 99%, not greater than about 95%.

Item 46. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition is formed from a mixture comprising a first content (Na1) of sodium oxide (Na2O) not greater than about 5 wt %, not greater than about 4 wt %, not greater than about 2 wt %, not greater than about 1 wt %, wherein the first pore defining composition is essentially free of sodium oxide.

Item 47. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition is formed from a mixture comprising a first content (Li1) of lithium oxide (Li2O) and the composition of the ceramic material comprises a second content (Li2) of lithium oxide different than the first content, wherein the first content is less than the second content, wherein the first content is less than the second content by at least about 1% based on the equation [|(Li1−Li2)|/(0.5*(Li1+Li2))]*100%, at least about 2%, at least about 3%, at least about 4%, at least about 5%, at least about 10%, at least about 15%, and not greater than about 99%, not greater than about 95%.

Item 48. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition is essentially free of lithium oxide (Li2O).

Item 49. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition is formed from a mixture comprising a first content (Fe1) of iron oxide (Fe₂O₃) and the composition of the ceramic material comprises a second content (Fe2) of iron oxide different than the first content, wherein the first content is less than the second content, wherein the first content is less than the second content by at least about 1% based on the equation [|(Fe1−Fe 2)|/(0.5*(Fe1+Fe2))]*100%, at least about 2%, at least about 3%, at least about 4%, at least about 5%, at least about 10%, at least about 15%, and not greater than about 99%, not greater than about 95%.

Item 50. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition is essentially free of iron oxide (Fe2O3).

Item 51. The composite body of any one of items 1, 2, 3, and 4, wherein the first pore defining composition is formed from a mixture comprising a first content (P1) of phosphorus oxide (P2O3) not greater than about 5 wt % for the total weight of the mixture, not greater than about 4wt %, not greater than about 2wt %, not greater than about 1 wt %, wherein the first pore defining composition is essentially free of phosphorus oxide (P2O3).

Item 52. The composite body of any one of items 1, 2, 3, and 4, further comprising abrasive particles contained within the bond material, wherein the abrasive particles include a material selected from the group consisting of an oxide, a carbide, a nitride, a boride, an oxynitride, an oxycarbide, an oxyboride, and a combination thereof, wherein the abrasive particles comprise a superabrasive material, wherein the abrasive particles include cubic boron nitride, wherein the abrasive particles comprise diamond.

Item 53. The composite body of item 52, further comprising a reaction product at an interface between the abrasive particles and the bond material, wherein the reaction product comprises a nitride, wherein the reaction product comprises a transition metal nitride, wherein the transition metal nitride compound is selected from the group consisting of TiN, CrN, VN, ZrN, and NbN.

Item 54. The composite body of item 53, wherein the bond material comprises not greater than about 15 mol % TiN.

Item 55. The composite body of item 53, wherein the transition metal nitride compound comprises CrN, wherein the bond material comprises not greater than about 15 mol % CrN.

Item 56. The composite body of item 53, wherein not less than about 50 vol % of the transition metal nitride is in direct contact with the abrasive particles.

Item 57. The composite body of item 53, wherein the transition metal nitride covers not less than about 30% of the surface area of the abrasive particles.

Item 58. The composite body of any one of items 1, 2, 3, and 4, wherein the bond material comprises not greater than about 80 mol % silicon dioxide.

Item 59. The composite body of any one of items 1, 2, 3, and 4, wherein the bond material comprises not less than about 10 mol % silicon dioxide.

Item 60. The composite body of any one of items 1, 2, 3, and 4, wherein the bond material comprises not greater than about 60 mol % aluminum oxide.

Item 61. The composite body of any one of items 1, 2, 3, and 4, wherein the bond material further comprises at least one element selected from the group of elements consisting of lithium oxide, magnesium oxide, calcium oxide, barium oxide, sodium oxide, potassium oxide, boron oxide, zirconium oxide, titanium oxide, zinc oxide, yttrium oxide, iron oxide, cesium oxide, lanthanum oxide, and bismuth oxide.

Item 62. The composite body of any one of items 1, 2, 3, and 4, wherein the abrasive particles comprise not less than about 25 vol % of the total volume of the composite body.

Item 63. The composite body of any one of items 1, 2, 3, and 4, wherein the bond material comprises not greater than about 60 vol % of the total volume of the bonded abrasive.

Item 64. The composite body of any one of items 1, 2, 3, and 4, wherein the bond material comprises a polycrystalline phase.

Item 65. The composite body of item 64, wherein the bond material comprises not less than about 50 vol % of the polycrystalline ceramic phase.

Item 66. The composite body of item 64, wherein the polycrystalline ceramic phase comprises crystallites having an average crystallite size of not less than about 0.05 microns.

Item 67. The composite body of any one of items 1, 2, 3, and 4, wherein the bond material comprises an amorphous phase.

Item 68. The composite body of any one of items 1, 2, 3, and 4, wherein the amount of not greater than about 10 vol % of the total volume of the bond material.

Item 69. The composite body of any one of items 1, 2, 3, and 4, wherein the composite body comprises a content of porosity of at least about 5 vol % of a total volume of the composite body.

Item 70. The composite body of item 69, wherein the content of porosity is not greater than about 50 vol % of the total volume of the bonded abrasive.

Item 71. The composite body of any one of items 1, 2, 3, and 4, wherein the body comprises a plurality of pores and wherein the average pore size is not greater than about 500 microns.

Item 72. The composite body of any one of items 1, 2, 3, and 4, wherein the body comprises a modulus of rupture (MOR) not less than about 20 MPa.

Item 73. The composite body of any one of items 1, 2, 3, and 4, wherein the body comprises a modulus of elasticity (MOE) not less than about 40 GPa.

Item 74. The composite body of any one of items 1, 2, 3, and 4, wherein is formed from a glass powder comprising a metal oxide compound described by the general equation aM2O-bMO-cM2O3-dMO2, wherein the amount (mol fraction) of the metal oxide compounds comprises 0.30>a>0, 0.60>b>0, 0.50>c>0, and 0.80>d>0.20.

Item 75. The composite body of item 74, wherein the glass powder comprises a metal oxide compound described by the general equation aM2O-bMO-cM2O3-dMO2, wherein the amount (mol fraction) of the metal oxide compounds comprises 0.15>a>0, 0.45>b>0, 0.40>c>0, and 0.75>d>0.30.

Item 76. The composite body of item 74, wherein the glass powder comprises a metal oxide compound described by the general equation aM2O-bMO-cM2O3-dMO2, wherein the amount (mol fraction) of the metal oxide compounds comprises 0.10>a>0, 0.35>b>0.15, 0.30>c>0.10, and 0.60>d>0.40.

Item 77. The composite body of item 74, wherein the metal oxide compound M2O comprises one of the metal oxide compounds selected from the group consisting of Li2O, Na2O, K2O, and Cs2O.

Item 78. The composite body of item 74, wherein the metal oxide compound MO comprises one of the metal oxide compounds selected from the group consisting of MgO, CaO, SrO, BaO, and ZnO.

Item 79. The composite body of item 74, wherein the metal oxide compound M2O3 comprises one of the metal oxide compounds selected from the group consisting of Al2O3, B2O3, Y2O3, Fe2O3, Bi2O3, and La2O3.

Item 80. The composite body of item 74, wherein the metal oxide compound dMO2 comprises one of the metal oxide compounds selected from the group consisting of SiO2, TiO2, and ZrO2.

Item 81. The composite body of any one of items 1, 2, 3, and 4, wherein the bond material comprises silicon dioxide in an amount between about 40 mol % and about 60 mol %, aluminum oxide in an amount within a range between about 10 mol % and about 30 mol %, and magnesium oxide in an amount within a range between about 15 mol % and about 35 mol %.

Item 82. A method of forming a composite body comprising:

providing a mixture comprising:

-   -   a bond material precursor powder; and     -   a pore former comprising a first pore former composition;

forming the mixture into a composite body comprising a bond material including a ceramic material and a region surrounding a pore in the bond material,

wherein the ceramic material comprises a composition and the region surrounding the pore comprises a first pore defining composition, and

wherein the first pore defining composition has a melting point not less than a melting point of a composition of the ceramic material.

Item 83. The method of item 82, wherein the pore former comprises a hollow object, wherein the pore former comprises a hollow spheroid, wherein the pore former comprises a hollow spheroid having a wall defining an interior space, and wherein the wall comprises the first composition.

Item 84. The method of item 83, wherein the wall has an average thickness of not greater than about 200 microns, not greater than about 100 microns, and at least about 1 micron.

Item 85. The method of item 82, wherein the first pore former composition comprises a ceramic material.

Item 86. The method of item 82, wherein the first pore former composition comprises at least one material selected from the group consisting of a polycrystalline material, an amorphous phase material, and a combination thereof.

Item 87. The method of item 82, wherein the first pore former composition comprises a crystalline material selected from the group consisting of cordierite, indialite, enstatite, sapphirine, anorthite, celsian, diopside, spinel, beta-spodumene, and a combination thereof.

Item 88. The method of item 82, wherein forming the mixture into a composite body comprises a process selected from the group consisting of molding, pressing, depositing, casting, extruding, heating, cooling, crystallization, melting, and a combination thereof.

Item 89. The method of item 82, wherein forming the mixture into a composite body comprises heating the mixture to a temperature below a melting point of the first pore former composition.

Item 90. The method of item 82, wherein forming the mixture into a composite body comprises treating the mixture at a temperature wherein the bond material precursor powder has a viscosity less than a viscosity of the first pore former composition of the pore former.

Item 91. The method of item 82, wherein forming the mixture into a composite comprises treating the mixture at a temperature sufficient to melt a significant portion of the bond material precursor powder while maintaining a substantially solid state of the first pore former composition of the pore former.

Item 92. The method of item 82, wherein forming the mixture into a composite body comprises treating the mixture at a temperature to change the bond material precursor powder to a three dimensional matrix of bond material and limiting the dissociation of the pore former into the bond material.

Item 93. The method of item 82, wherein the mixture further comprises abrasive particles.

Item 94. The method of item 82, wherein the first pore former composition has a first hardness (H1) and the composition of the ceramic material has a second hardness (H2), and wherein first hardness is not less than the second hardness.

Item 95. The method of item 82, wherein forming the mixture into a composite body comprises heating the green article at a transformation temperature to form abrasive particles in a vitreous bond material, the transformation temperature changing a transition metal oxide compound of the mixture to a transition metal nitride compound at the interface of an abrasive particle of the mixture and the vitreous bond material.

Item 96. The method of item 82, wherein forming the mixture into a composite body comprises a controlled cooling after heating to form a polycrystalline material within the bond material.

Item 97. The method of item 82, wherein the mixture further comprises a binder selected from the group of organic materials consisting of glycol, dextrin, resin, polyethylene, ethylene, propylene, glue, and polyvinyl alcohol.

EXAMPLES

FIGS. 4A, 4B and 5 illustrate the difference in appearance between pore forming material in conventional composite bodies and composite bodies that include pore forming material as shown in embodiments described herein.

FIGS. 4A and 4B illustrate a composite body 400 having a bond material 403, pores 404 within the bond material, and a pore defining region 406 of the bond material 403 surrounding the pores 404. Pore defining region 406 shows the remnants of the pore formers, which were combined in a mixture with the bond material during the formation process. As is shown in FIG. 4A, the pore defining region 406 of a conventional composite body does not maintain demarcation of the original shape of the pore former, but rather the pore defining region merges into the bond material 403.

For comparison, FIG. 5 illustrates a composite body 500 having a bond material 503, pores 504 within the bond material 503 and a pore defining region 506 of the bond material 503 surrounding the pores 504. Pore defining region 506 shows the remnants of the pore formers, which were combined in a mixture with the bond material during the formation process. As is shown in FIG. 5, the pore defining region 506 shows clear demarcation of the remnants of the original shape of the pore former, with little, if no, infiltration or mixture into the bond material.

Generally, the composite bodies provided herein exhibit improved grinding performance, particularly, improved composite body wear, free grinding behavior, power draw and lower forces per grit.

In the foregoing, reference to specific embodiments and the connections of certain components is illustrative. It will be appreciated that reference to components as being coupled or connected is intended to disclose either direct connection between said components or indirect connection through one or more intervening components as will be appreciated to carry out the methods as discussed herein. As such, the above-disclosed subject matter is to be considered illustrative, and not restrictive, and the appended claims are intended to cover all such modifications, enhancements, and other embodiments, which fall within the true scope of the present invention. Thus, to the maximum extent allowed by law, the scope of the present invention is to be determined by the broadest permissible interpretation of the following claims and their equivalents, and shall not be restricted or limited by the foregoing detailed description.

The Abstract of the Disclosure is provided to comply with Patent Law and is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, various features may be grouped together or described in a single embodiment for the purpose of streamlining the disclosure. This disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter may be directed to less than all features of any of the disclosed embodiments. Thus, the following claims are incorporated into the Detailed Description, with each claim standing on its own as defining separately claimed subject matter 

What is claimed is:
 1. A composite body comprising: a bond material comprising a ceramic material; and a pore within the ceramic material; wherein a region of the bond material at a surface of the pore defines a first pore defining composition distinct from a composition of the ceramic material, the first pore defining composition having a melting point not less than a melting point of the composition of the ceramic material.
 2. The composite body of claim 1, wherein the ceramic material comprises a material selected from the group consisting of an amorphous phase, a polycrystalline phase, and a combination thereof.
 3. The composite body of claim 1, wherein the first pore defining composition comprises a first crystalline content (C1) and the ceramic material comprises a second crystalline content (C2), wherein the first crystalline content is different than the second crystalline content
 4. The composite body of claim 1, wherein the first pore defining composition comprises a first amorphous content (A1) and the ceramic material comprises a second amorphous content (A2), wherein the first amorphous content is different than the second amorphous content.
 5. The composite body of claim 1, wherein a peripheral region of the bond material defined by at least a portion of a surface defining the opening and extending for a depth into the bond material has a first pore defining composition distinct from a composition of the ceramic material, the first pore defining composition having a melting point not less than a melting point of the composition of the ceramic material.
 6. The composite body of claim 5, wherein the depth is not greater than a diameter of the pore.
 7. The composite body of claim 1, wherein the first pore defining composition has a first hardness (H1) and the composition of the ceramic material has a second hardness (H2), and wherein first hardness is not less than the second hardness.
 8. The composite body of claim 7, wherein the first hardness is different from the second hardness by at least about 1% based on the equation [|(H1−H2)|/(0.5*(H1+H2))]*100%.
 9. The composite body of claim 1, wherein the first pore defining composition comprises a crystalline phase selected from the group consisting of cordierite, indialite, enstatite, sapphirine, anorthite, celsian, diopside, spinel, beta-spodumene, and a combination thereof.
 10. The composite body of claim 1, wherein the first pore defining composition is formed from a mixture comprising at least about 30 wt % and not greater than about 50 wt % silicon dioxide (SiO₂) for a total weight of the mixture.
 11. The composite body of claim 1, wherein the first pore defining composition is formed from a mixture comprising at least about 20 wt % and not greater than about 38 wt % aluminum oxide (Al₃O₂) for a total weight of the mixture.
 12. A composite body comprising: a bond material comprising a ceramic material; and a pore within the ceramic material; wherein a region of the bond material at a surface of the pore defines a first pore defining composition distinct from a composition of the ceramic material; wherein the first composition has a first hardness (H1) and the composition of the ceramic material has a second hardness (H2); and wherein the first hardness is not less than the second hardness.
 13. The composite body of claim 12, wherein the first pore defining composition comprises a first crystalline content (C1) and the ceramic material comprises a second crystalline content (C2), wherein the first crystalline content is different than the second crystalline content
 14. The composite body of claim 12, wherein the first pore defining composition comprises a first amorphous content (A1) and the ceramic material comprises a second amorphous content (A2), wherein the first amorphous content is different than the second amorphous content.
 15. The composite body of claim 12, wherein the first pore defining composition comprises a crystalline phase selected from the group consisting of cordierite, indialite, enstatite, sapphirine, anorthite, celsian, diopside, spinel, beta-spodumene, and a combination thereof.
 16. The composite body of claim 12, wherein the first pore defining composition is formed from a mixture comprising at least about 30 wt % and not greater than about 50 wt % silicon dioxide (SiO₂) for a total weight of the mixture.
 17. The composite body of claim 12, wherein the first pore defining composition is formed from a mixture comprising at least about 20 wt % and not greater than about 38 wt % aluminum oxide (Al₃O₂) for a total weight of the mixture.
 18. A method of forming a composite body comprising: providing a mixture comprising: a bond material precursor powder; and a pore former comprising a first pore former composition; forming the mixture into a composite body comprising a bond material including a ceramic material and a region surrounding a pore in the bond material, wherein the ceramic material comprises a composition and the region surrounding the pore comprises a first pore defining composition, and wherein the first pore defining composition has a melting point not less than a melting point of a composition of the ceramic material.
 19. The method of claim 18, wherein the wall has an average thickness of not greater than about 200 microns and at least about 1 micron.
 20. The method of claim 18, wherein the first pore former composition has a first hardness (H1) and the composition of the ceramic material has a second hardness (H2), and wherein first hardness is not less than the second hardness. 